A Silesian manufacturing company faces a contractual dispute worth PLN 8 million. The opposing party's technical expert has submitted a report that contradicts the client's own engineering analysis. The court has scheduled a hearing in six weeks. Without a properly appointed counter-expert or a successful challenge to the existing opinion, the client risks forfeiting a claim it would otherwise win on the merits.
In Polish court proceedings, expert witnesses are appointed by the court from a list maintained by the relevant sąd okręgowy (regional court) or from a national register held by the Minister Sprawiedliwości (Minister of Justice). The court expert's opinion carries significant evidentiary weight. Parties may challenge it, request supplementation, or commission a private opinion – but only within strict procedural deadlines set by the Kodeks postępowania cywilnego (Code of Civil Procedure, KPC).
This guide walks through the full lifecycle of expert evidence in Polish civil litigation: how experts are appointed, how opinions are challenged, what private opinions can and cannot achieve, and how foreign investors should prepare before disputes escalate. Three business scenarios – manufacturing, IT services, and cross-border investment – illustrate the procedural choices at each stage.
How are expert witnesses appointed in Polish proceedings?
Court appointment is the default. The court issues a formal decision designating a specific expert, defining the scope of the questions to be answered, and setting a deadline for submission of the written opinion – typically 30 to 90 days from the decision. The expert is drawn from the regional court's register or, where no suitable specialist exists locally, from the national register maintained by the Ministry of Justice.
Parties have a limited but meaningful role at this stage. Each side may propose questions for the expert to address. The court is not obliged to accept all proposed questions, but a well-drafted submission materially shapes the scope of the opinion. Missing this window forfeits the opportunity to direct the expert's analysis toward the issues that matter most to your case.
The National Court Register (KRS) does not govern expert registration directly, but corporate parties appearing before Polish courts are identified through KRS records, and the court verifies standing before appointing experts in disputes involving legal entities. The Polish Financial Supervision Authority (KNF) becomes relevant where the dispute touches on regulated financial instruments – in those cases, the court may appoint an expert with KNF-adjacent credentials.
- Submit proposed expert questions within the deadline set by the court's procedural order.
- Verify the appointed expert's registration status on the Ministry of Justice portal.
- Check for conflicts of interest before the expert submits the opinion.
- Request that the court specify the deadline for the opinion in the appointment decision.
Costs at this stage are borne initially by the party that requested the expert, or shared if the court appoints on its own motion. The advance payment (zaliczka) typically ranges from PLN 3,000 to PLN 15,000 depending on the complexity of the field. Final allocation follows the outcome of the case.
What procedural steps govern the submission and challenge of expert opinions?
Once the written opinion is filed, parties receive a copy and a deadline – usually 14 days – to submit written observations. This is the first and most important opportunity to challenge the opinion's methodology, factual assumptions, or conclusions. Failure to raise objections at this stage significantly weakens any later attempt to have the opinion set aside or supplemented.
We secured a reversal of an adverse expert opinion for a technology client in the Mazowieckie region (autumn 2025). The expert had applied an outdated valuation standard. We identified the error in the written observations stage, requested supplementation, and the court ultimately ordered a second opinion from a different expert – which supported our client's position.
Three procedural instruments are available after the opinion is filed. First, the party may request written supplementation (uzupełnienie opinii), asking the expert to address gaps or ambiguities. Second, the party may request that the expert appear at a hearing for oral questioning. Third – and most consequential – the party may request appointment of a different expert on grounds that the original opinion is internally inconsistent or methodologically flawed. The court grants the third option sparingly; a well-reasoned motion supported by a private opinion has the best chance of success.
A private opinion (opinia prywatna) commissioned by a party does not have the procedural status of a court expert's opinion. Under Polish civil procedure, it is treated as a party's own submission. However, it serves a vital strategic function: courts regularly use private opinions as the basis for ordering a new court-appointed expert, particularly where the private opinion identifies specific methodological errors in the original report.
Timeline matters here. From opinion filing to the next hearing, parties in Warsaw district courts typically have four to eight weeks. In the Silesia region, timelines can extend to twelve weeks. Planning the challenge strategy before the opinion arrives – not after – is the difference between a controlled response and a reactive scramble.
How should foreign investors prepare for expert evidence in Polish disputes?
For a German investor entering a Polish construction dispute, the expert evidence phase is often the point at which local procedural knowledge determines the outcome. Polish expert witnesses operate under the KPC framework, not under IBA Rules on the Taking of Evidence or common-law expert protocols. The differences are material and frequently underestimated by foreign counsel unfamiliar with Polish litigation Warsaw practice.
Our team obtained interim measures protecting assets worth over EUR 3m for a Dutch investor's subsidiary in Lower Silesia (spring 2026). The underlying dispute required expert evidence on construction defects. Early coordination between the client's German technical consultants and Polish litigation counsel ensured that the proposed expert questions were framed in terms the Polish court would accept – avoiding the translation and framing errors that cost parties weeks of procedural delay.
Three preparation steps matter most for cross-border clients. First, identify the field of expertise required and check whether the regional court's register contains qualified specialists. Where it does not – common in highly technical IT or pharmaceutical disputes – the court will turn to the national register, adding six to ten weeks to the timeline. Second, prepare a bilingual technical summary of the factual issues before the first hearing; this document shapes the court's formulation of expert questions. Third, engage Polish litigation counsel at least 60 days before the hearing at which expert appointment is likely to be ordered.
Sanctions compliance issues occasionally intersect with Polish court proceedings – for example, where a party seeks to enforce a contract that may involve a sanctioned entity or jurisdiction. In those cases, the court may appoint an expert in international trade law or financial regulation alongside the primary technical expert. Parties should anticipate this possibility and prepare accordingly. For disputes with a cross-border dimension, our guide on enforcing a Luxembourg judgment in Poland addresses the parallel procedural track that often runs alongside domestic expert proceedings.
The KIO (National Appeals Chamber, Krajowa Izba Odwoławcza) operates a separate expert evidence framework for public procurement disputes. A KIO appeal involving technical specifications or price abnormality assessments will engage expert evidence rules that differ from civil court procedure. Parties familiar with civil litigation should not assume the same timelines or challenge mechanisms apply in KIO proceedings.
To receive an expert assessment of your cross-border dispute strategy in Poland, contact info@kordeckipartners.com.
The specific facts of your matter will determine which procedural instruments are available and which carry the greatest risk of preclusion if not used promptly. Waiting until after the expert opinion is filed to engage Polish counsel forfeits the most valuable window – the question-formulation stage.
What are the most common mistakes parties make with expert evidence?
The most costly mistake is passive acceptance of the appointed expert's opinion. Polish courts give court-appointed experts considerable deference. An unchallenged opinion – even a flawed one – frequently becomes the evidentiary foundation of the judgment. Parties that do not engage actively at the observations stage lose the ability to reopen the expert evidence question on appeal without demonstrating that they raised the issue below.
A second common error involves the timing of private opinions. Commissioning a private opinion after the court has already incorporated the court expert's findings into its reasoning is procedurally late. The private opinion must arrive in time to support a motion for a new court-appointed expert – ideally within the 14-day observations window. A report delivered two weeks after that deadline has no procedural traction.
Three business scenarios illustrate the pattern:
- Manufacturing (Silesia): A supplier dispute over defective components. The court expert applies a standard from 2018. The party fails to flag the outdated standard in written observations. The appeal court refuses to admit new expert evidence because the issue was not raised at first instance.
- IT services (Mazowieckie): A software development contract dispute. The appointed expert lacks specific SaaS valuation credentials. The party challenges appointment within five days of the decision. The court accepts the challenge and appoints a specialist from the national register.
- Foreign investor (Pomerania): A real estate acquisition dispute. The investor's foreign counsel submits expert questions in English. The court rejects them as procedurally non-compliant. Polish-language questions submitted by local counsel are accepted without issue.
A fourth mistake – less common but irreversible – is failing to object to an expert's conflict of interest before the opinion is submitted. Under Polish civil procedure, a conflict of interest objection raised after the opinion has been filed is treated as untimely. The expert's prior relationship with the opposing party, if known and not raised promptly, cannot be used to challenge the opinion's admissibility. This forfeits a potentially decisive procedural weapon.
Employment-related disputes sometimes require expert evidence on remuneration benchmarks or workplace conditions. Parties in those proceedings should be aware of the interaction between expert evidence rules and the employment law framework – a dimension explored further in our analysis of B2B reclassification risk and enforcement powers.
For parties pursuing or defending claims across multiple jurisdictions, the arbitration Poland framework offers an alternative to Polish state court proceedings. Expert evidence in arbitration is governed by the arbitration rules chosen by the parties – typically allowing greater flexibility in expert selection and questioning than the KPC regime. Our cross-border disputes practice covers both tracks. See our overview of the disputes practice in Spain for a comparative view of how expert evidence operates in a civil-law jurisdiction with structural similarities to the Polish system.
For a tailored strategy on managing expert evidence in your Polish dispute, reach out to info@kordeckipartners.com.
A specific dispute situation – particularly one approaching the observations deadline or a hearing date – requires immediate attention. Delay at this stage precludes procedural instruments that cannot be recovered on appeal.
What to prepare: expert evidence checklist
Preparation before the expert appointment decision is issued determines the quality of the evidentiary record. Parties that arrive at the appointment hearing with a prepared set of proposed questions and a verified list of qualified experts in the relevant field control the process. Those that react after the fact spend the remainder of the proceedings correcting avoidable errors.
The following checklist applies to civil court proceedings before Polish district and regional courts. KIO appeal proceedings and arbitration Poland matters require adapted versions.
- Identify the precise technical or scientific questions at issue before the first case management hearing.
- Verify the regional court's expert register for qualified specialists in the relevant field.
- Prepare proposed expert questions in Polish, reviewed by Polish litigation counsel.
- Commission a preliminary private opinion to identify the methodological standards the court expert should apply.
- Set a 14-day internal deadline from receipt of the court expert's opinion to file written observations.
Cost planning is part of preparation. Expert fees in complex commercial disputes regularly reach PLN 20,000 to PLN 50,000 per opinion. Where multiple experts are appointed – common in construction and IT disputes – total expert costs can exceed PLN 100,000. These amounts are recoverable from the losing party, but only if claimed correctly in the cost summary submitted at the close of proceedings.
A dispute lawyer handling the matter should coordinate expert strategy from the outset, not treat it as a standalone procedural step. The questions posed to the expert, the observations filed in response, and any motion for a second opinion form a connected evidentiary chain. A gap at any point weakens the chain as a whole.
Frequently asked questions
Q: How long does it take to receive a court expert's opinion in a Polish commercial dispute?
A: The court sets a deadline in the appointment decision, typically 30 to 90 days. In practice, experts in complex technical fields – construction, IT, financial valuation – regularly request extensions of 30 to 60 additional days. Parties should plan for a minimum of four months from the appointment decision to the opinion being filed, particularly in proceedings before Warsaw regional courts where caseloads are high.
Q: Can a party choose its own expert in Polish court proceedings?
A: No. The court appoints the expert. A party may propose a specific expert by name, and courts sometimes accept such proposals – particularly where the proposed expert is registered and has relevant credentials. However, the court retains full discretion. A private opinion commissioned by a party is treated as a party submission, not as expert evidence, and does not carry the same evidentiary weight as a court-appointed opinion.
Q: What is the cost of challenging a court expert's opinion in Poland?
A: There is no court fee for filing written observations or requesting supplementation. Requesting a second court-appointed expert requires a new advance payment, typically PLN 5,000 to PLN 20,000 depending on the field. A private opinion to support the challenge motion costs PLN 8,000 to PLN 30,000 in most commercial fields. All expert costs are subject to reallocation in the final cost order, so the net exposure depends on the outcome of the case.
KORDECKI & Partners is a law firm based in Warsaw and Krakow, advising business clients across 30 jurisdictions. Our team combines expertise in Polish and international law with a practical approach to commercial litigation, arbitration, and cross-border dispute resolution. We work with Polish entrepreneurs, foreign investors, and in-house legal teams navigating Polish court proceedings – including the management of expert evidence in high-value commercial disputes. To discuss your situation, contact info@kordeckipartners.com.
Disclaimer: This publication is provided for informational purposes only and does not constitute legal advice. The information herein should not be relied upon as a substitute for professional legal counsel tailored to your specific circumstances. KORDECKI & Partners assumes no liability for actions taken or not taken based on the contents of this material. For advice regarding your particular situation, please contact info@kordeckipartners.com.