A party can waive a right to object to a decision reached by a decision-maker guilty of bias, but the objection must be raised in a timely fashion before the decision is delivered; however, if statements made in the reasons for decision effectively revive and give greater substance to matters evident during the proceedings, waiver may not apply.

The test to be applied in Australia in determining whether a judge is disqualified by reason of appearance of bias is whether a fair-minded lay observer might reasonably apprehend that the judge might not bring an impartial and unprejudiced mind to the resolution of the question the judge is required to decide.

The hypothetical observer is to be taken to be reasonable and is observed as a professional judge whose training, tradition and oath require him to discard the irrelevant, the immaterial and the prejudicial.

The reasonableness of any suggested apprehension of bias is to be considered in the context of ordinary judicial practice, which is not frozen in time but develops to take account of the exigencies of modern litigation.

Judges at trial or appellate level who, in exchanges with counsel, express tentative views which reflect a certain tendency of mind, are not on that account alone to be taken to indicate prejudgment. Judges are not expected to sit mute, and will often form tentative opinions on matters in issue.

The effect of a statement that might indicate prejudgment can be removed by a later statement which withdraws or qualifies it, depending upon the circumstances of the particular case. The hypothetical observer is entitled to consider the effect of a later statement in the context of the earlier one.

Every adjudicator must be free from bias as a fundamental rule of natural justice and an abiding value of the legal system, with the foundation resting on the principle that parties and the public must have confidence in the impartiality and independence of decision-makers.

The test is expressed in terms of 'might' (possibilities) rather than 'high probability' or 'real danger', reflecting the importance attached to both the actuality of justice and the appearance of impartiality to parties and the community.

The fictitious reasonable bystander is not a lawyer, but neither is wholly uninformed about the law. Such a person would be aware that adjudicators sometimes express tentative opinions that may later change, and would not reach hasty conclusions based on isolated episodes taken out of context.

The ground of disqualification is a reasonable apprehension that the judicial officer will not decide the case impartially or without prejudice, rather than that he will decide the case adversely to one party.

The ground of disqualification is a reasonable apprehension that the judicial officer will not decide the case impartially or without prejudice, rather than that he will decide the case adversely to one party; previous decisions generating expectation of adverse decision do not provide acceptable basis for inferring reasonable apprehension of bias.

It is a fundamental principle that a judge must not hear evidence or receive representations from one side behind the back of the other, and a judge tries the case before him on the evidence and arguments presented in open court by the parties alone unless Parliament otherwise provides.