The freedom of the judiciary, both Judges and Magistrates, from control or influence by the Government is recognised as a fundamental constitutional principle and is strictly observed in practice. Judges and Magistrates are appointed by the Governor-General on the advice of the Minister of Justice. They are recruited from the legal profession, the qualification being seven years' practice (or, in the case of Magistrates, seven years' standing) as a barrister or solicitor. A qualified Court Registrar may be appointed as a Magistrate but this is seldom done. Appointments are not influenced by politics.

Judges of the Supreme Court hold office during good behaviour. They retire at 72 years. They may be removed by the Queen on an address from the House of Representatives, but this has never happened. There was said to be a convention that Judges in New Zealand received no promotion, and the practice is to appoint the Chief Justice direct from the practising profession. Since the reconstitution of the Court of Appeal, however, Supreme Court Judges have been appointed to that Court. A further supposed safeguard of independence is the statutory rule that a Judge's salary shall not be reduced while he holds office. It was on this ground that in 1932 during the depression the Judges are thought to have declined a request to forgo voluntarily part of their salary. The salary of Judges in office has, however, been increased from time to time. The withholding of an increase could be as much a threat to independence as a reduction. In truth, the real securities for judicial independence are public opinion, tradition, and the high integrity of those appointed as Judges.

Magistrates, who retire at 68, may be removed by the Governor-General for inability or misbehaviour. In practice the independence of the lower judiciary is as secure as that of the Judges.