Branches of government

The Constitution Act 1986 recognises the three branches of government – the legislature (Parliament), the executive (Cabinet and Ministers outside Cabinet, plus government departments), and the judiciary. Each operates independently of the others. This is known as "the separation of powers".

The judiciary is independent from the other branches to government to ensure impartial decision-making by judges. Judicial independence is fundamental to the constitutional balance under the Constitution Act 1986 and to the principle of legality that underlies it. When judging, judges should be subject only to the law. This principle is not unique to New Zealand – it is well recognised in other democratic countries and is also spelt out in international documents such as the Beijing Statement of Principles of the Independence of the Judiciary in the LAWASIA Region (19 August 1995); the United Nations Basic Principles on the Independence of the Judiciary (1985), and the International Covenant on Civil and Political Rights (1976).

The independence of judges is secured by ancient guarantees of security of tenure and salary (both of which are enshrined in ss 23 and 24 of the Constitution Act 1986) and by constitutional conventions which prevent the executive directing the judiciary. Parliament directs the judiciary only by legislation. In this context, an important constitutional convention is that the Attorney-General acts independently of political considerations in recommending judicial appointments.

Judges also have immunity from being sued in their private capacity in respect of actions taken against them in their role as judges. Judges are protected against removal from office except on the grounds of misbehaviour or incapacity. The removal process requires an address from the House of Representatives.

Independence does not prevent interaction between the various branches. The executive may consult the judiciary on policy and legislative proposals which impact upon the judiciary and the courts.  The judiciary may comment on issues relating to proposed and existing legislation that directly affect the operation of the courts, the independence of the judiciary, the rule of law, or the administration of justice. The Terms of Reference for the judiciary’s Legislation and Law Reform Committee provide more information on the relationship between the judiciary, the executive and Parliament on law reform matters.

For their part, members of the executive respect the judiciary. The formal position is set out in the Cabinet Manual, which states that:

"the separation of the Executive and the Judiciary under the New Zealand system of government means that Ministers must exercise prudent judgment before commenting on judicial decisions – either generally or in relation to the specifics of an individual case (for example, the sentence). Ministers, following long established principle, do not involve themselves in deciding whether a person should be prosecuted or on what charge. Therefore, they should not express comment on the results of particular cases or on any sentence handed down by a court. Sentencing is a complex process. Ministers must avoid commenting on any sentences within the appeal period and should avoid at all times any comment that could be construed as being intended to influence the courts in subsequent cases. It is, however, proper for Ministers to comment on the effectiveness of the law, or about policies on punishment (that is, on those matters where the Executive has a proper involvement), but not where the performance of the courts is brought into question."

The Chief Justice, as the head of the judiciary, is the primary point of contact between the executive and the judiciary. Heads of Bench may also communicate directly with the executive on matters of interest to their respective courts.

The Chief Justice occasionally attends Select Committees of the House considering legislation (for instance, relating to judicial disciplinary procedures), usually with other judges. Heads of Bench sometimes attend as well in respect of pending legislation relevant to their jurisdictions (for example, family or employment-related legislation).

The Statement of Principles (from 2018) sets out the principles observed by the judiciary and Ministry of Justice in the administration of the courts, and documents the responsibilities of the judiciary and Ministry in the operation of the courts.