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Appendix B: a comparison of the inquisitorial and adversarial systems


An inquisitorial system, common in civil law countries, is an alternative model to the adversarial system used in common law countries including New Zealand. The inquisitorial system is generally described as a system that aims to get to the truth of the matter through extensive investigation and examination of all evidence. The adversarial system aims to get to the truth through the open competition between the prosecution and the defence to make the most compelling argument for their case. Critics of the adversarial approach argue that the pursuit of winning often overshadows the search for truth.

Neither system is inherently superior. In fact there are many shared features and many countries incorporate features of both systems, having experienced a degree of convergence over the last 80 years. [73]

An option for New Zealand may be to incorporate aspects of inquisitorial systems within our adversarial system, as already happens in some courts and tribunals, rather than to adopt an entirely new approach.  However, we need to be careful when adopting individual features on another system, and recognise that individual features fit into a wider system that may often provide support and balance.  Any changes also need to be considered within the context of New Zealand’s well-established common law criminal justice system.

The following table outlines the fundamental differences (and areas of convergence) between typical adversarial and inquisitorial systems:


adversarial systems inquisitorial systems
Binding force of case law Previous decisions by higher courts are binding on lower courts.  Traditionally, there is little use of judicial precedent (case law). This means Judges are free to decide each case independently of previous decisions, by applying the relevant statutes.  There is therefore heavier reliance on comprehensive statutes/codes of law. 
Investigation The responsibility for gathering evidence rests with the parties (the Police and the defence). 

The typical criminal proceeding is divided into 3 phases: the investigate phase, the examining phase, and the trial.

In the investigative phase, a government official (generally the public prosecutor) collects evidence and decides whether to press charges.  Prosecutors carry out investigations themselves or request Police to do so. The prosecution can give general instructions to the Police regarding how particular cases are to be handled and can set areas of priority for investigations.

In some inquisitorial systems, a Judge may carry out or oversee the investigative phase.

Examining phase There is no examination phase, so an independent evaluation of the evidence collected during investigation is left to the trial.

The examining phase is usually conducted in writing.  An examining Judge completes and reviews the written record and decides whether the case should proceed to trial.

The examining Judge plays an active role in the collection of evidence and interrogation of witnesses. In some inquisitorial systems, the “legality principle” dictates that prosecution must take place in all cases in which sufficient evidence exists (ie, the prosecutor or Judge has limited discretion as to whether or not charges will be brought).

The trial

An adversarial system requires the prosecutor, acting on behalf of the State, and the defence lawyer, acting on behalf of the accused, to offer their version of events and argue their case before an impartial adjudicator (a Judge and/or jury).

Each witness gives their evidence-in-chief (orally) and may be cross-examined by opposing counsel and re-examined. [74]

As a result of the thoroughness of the examining phase, a record of evidence has already been made and is equally available to the prosecution and defence well in advance of the trial.

The main function of a trial is to present the case to the trial Judge and, in some cases, the jury, and to allow the lawyers to present oral argument in public.

While there is no cross- and re-examination of witnesses, witnesses are still questioned and challenged.

In Germany there is a preference for narrative testimony, in which the witness gives their version of events without shaping by questions from the prosecution or defence. [75]

Traditionally there is no ability for the defendant to plead guilty.

Role of the trial Judge and counsel The Judge is a referee at the hearing. It is the Judge’s function to ensure that the court case is conducted in a manner that observes due process.  The Judge decides whether the defendant is guilty beyond reasonable doubt (except in jury trials where the jury performs that role), and determines the sentence.

Lawyers are primarily responsible for introducing evidence and questioning witnesses.

Judges are required to direct the courtroom debate and to come to a final decision.

The Judge assumes the role of principal interrogator of witnesses and the defendant, and is under an obligation to take evidence until he or she ascertains the truth.

It is the Judge that carries out most of the examination of witnesses, arising from their obligation to inquire into the charges and to evaluate all relevant evidence in reaching their decision. [76]

However, it is now accepted that the defence should have the right to confront each witness during at least one stage in the proceedings. [77

Use of juries  Juries are used in many cases. In New Zealand, if the maximum sentence of the charge is more than three months, the defendant has the right to elect trial by jury. [78] Juries are generally only used for the most serious cases.
Rules of evidence

Evidence which is prejudicial or of little probative value, is more likely to be withheld from juries (who don’t have training on the weight that should be given to certain evidence).  However, hearsay evidence is more readily allowable if it is reliable.

A significant category of inadmissible evidence is ‘hearsay’ evidence (with numerous exceptions).  In New Zealand, a ‘hearsay statement’ is defined in the Evidence Act 2006 as “a statement that was made by a person other than a witness and is offered in evidence at the proceedings to prove the truth of its contents”.

At the heart of the hearsay rule is the idea that, if the court is to discover the truth, it is essential that parties have the opportunity to verify the information provided by the witnesses, which is difficult to do if the court receives evidence in writing or via a third party (and are therefore unable to cross-examine the person).

The rules around admissibility of evidence are significantly more lenient.  The absence of juries in many cases alleviates the need for many formal rules of evidence.  More evidence is likely to be admitted, regardless of its reliability or prejudicial effect.  Evidence is admitted if the Judge decides it is relevant.

In many inquisitorial systems, there is no hearsay rule (eg, France, Belgium and Germany).  It is up to the Judge to decide the value of such testimony.

Rights of the defendant

In both systems the accused is protected from self-incrimination and guaranteed the right to a fair trial.

However, some commentators view adversarial systems as offering stronger protections for defendants due to their interpretation of the right to silence. 

In both systems the accused is protected from self-incrimination and guaranteed the right to a fair trial.
Role of the victim

Victims are not a party to proceedings.  Prosecutors act on behalf of the State and do not represent the victim.

In New Zealand, victims can provide a victim impact statement to the court at sentencing, which the Judge must take into account when determining the offender’s sentence.

The victim generally has a more recognised role in inquisitorial systems – they usually have the status of a party to proceedings.

In some jurisdictions, victims have a formal role in the pre-trial investigative stage, including a recognised right to request particular lines of inquiry or to participate in interviews by the investigating authority.

At the trial, they generally have independent standing and some jurisdictions allow victims to be represented by their own lawyer.

Organisation of the courts Adversarial systems have courts of general jurisdiction available to adjudicate a wide range of cases. Civil law systems tend to have specialist courts (and specialist appeal courts) to deal with constitutional law, criminal law, administrative law, commercial law, and civil or private law.



73. Zweigert, K. et al, An Introduction to Comparative Law, Clarendon Press, 3rd edition, 1998, p 271.

74. In New Zealand, defendants have the right to examine the witnesses for the prosecution under section 25(f) of the New Zealand Bill of Rights Act 1990.

75. Pizzi et al., (1996), above n 76, p 37.

76. Pizzi, William T, and Walter Perron, Crime Victims in German Courtrooms: A Comparative Perspective on American Problems, Stanford Journal of International Law, Vol 32, 1996, p 37.

77. J R Spencer, ‘Evidence’ in European Criminal Procedures, Eds Delmas-Marty M and Spencer, J.R., Cambridge University Press, 2002.

78. This is provided by section 24(e) of the New Zealand Bill of Rights Act 1990.  However, there is a proposal in the Criminal Procedure (Reform and Modernisation) Bill to change this to three years.

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