The popular Australian media often refers to calls for a ‘judicial inquiry’. There is actually no such thing in Australia (or Canada) – this term is incorrect and quite misleading.
Whilst Royal Commissions and other boards of inquiry are sometimes (but not necessarily) chaired by retired or sitting judges, they are not acting in their capacity as judges when conducting a public inquiry. Thus these inquiries are not part of the judicial system – they are appointed by and are part of the executive branch of government. They do not ‘sit in judgement’ – all they can do is to make recommendations to government.
Associate Chief Justice Dennis R. O’Connor of Ontario, Canada has put it this way:
‘There is some debate as to whether sitting judges should serve as commissioners of independent inquiries. Conducting an inquiry is not part of the judicial role nor involves judicial duties. The creation of an inquiry is an act of the executive. A judge who serves as a commissioner is carrying out a function of the executive, not the judicial branch of government. The judge as commissioner does not adjudicate on issues of civil or criminal liability. The findings and recommendations in a report have no binding legal effect. The judge fulfills the function frequently carried out by non-judicial investigators or committees.'
The Australian High Court has cited the opinion of the Supreme Court of the United States in Mistretta v United States  :
‘The legitimacy of the Judicial Branch ultimately depends upon its reputation for impartiality and nonpartisanship. That reputation may not be borrowed by the political Branches to cloak their work in the neutral colors of judicial action.’
The former Chief Justice of Australia, Murray Gleeson has commented:
‘That is a salutary warning even in jurisdictions where there is no constitutionally required separation of powers, such as the Australian States. There are well understood practical dangers of judges being drawn into political controversy by an injudicious decision to take on an inquiry in which partisan interests are involved. It may be that the reason why the executive seeks a judge for an inquiry is that it is obvious that it may arouse political passions, and it is hoped they may be cooled by a neutral inquirer. That might be a good reason for the judiciary to decline to be drawn in. What is worse, however, is a case where an inquiry is given a task which is of such a nature that its performance cannot be completely independent of executive or legislative influence. It is one thing to seek to turn the judiciary’s reputation for impartiality to public advantage; it is another thing to use that reputation to give to partisan executive or legislative action a spurious appearance of impartiality.'
In 1923, Chief Justice Irvine wrote to the Victorian Attorney-General declining a request that he invite one of the judges of the Supreme Court of Victoria to undertake a Royal Commission, and expressing the view that it was generally inappropriate for judges to do other than hear and determine issues of fact and law in the context of the resolution of a justiciable controversy. In 1954, the judges of the Supreme Court of Victoria, with the support of the Victorian Bar, adopted a resolution that, except in a matter of national importance arising in times of national emergency, it is undesirable that any judge should accept nomination as a Royal Commissioner. The Chief Justice of Victoria has told former Chief Justice Gleeson that this remains the view of her Court.
 The Hon. Associate Chief Justice Dennis R. O’Connor ‘Some Observations on Public Inquiries’, Canadian Institute for the Administration of Justice, Annual Conference. October 10, 2007, Halifax, Nova Scotia.
 US Supreme Court Decision. Mistretta v United States 488 US 361 at 407 (1989).
 Murray Gleeson, ‘The Right to an Independent Judiciary’ Speech to 14th Commonwealth Law Conference, London, September 2005.