One well known rule of natural justice is that everybody has a right to a fair trial before an impartial court.

Another is that each party to a case has the right to be heard.

Natural justice also requires that appropriate notice be given of a hearing where a person's rights are at issue; that reasonable opportunity must be given to prepare and present a case, including calling relevant witnesses; and that a person cannot be the judge in a case or dispute in which they have a personal interest.

A legislature has the power to override these 'rules' if it wishes to do so, but it must do so expressly or by necessary implication. Otherwise the courts will adhere to the rules of natural justice when interpreting legislation.