Refers to decisions made by administrative tribunals or government officials to which the rules of natural justice apply. In judicial decisions, the principles of natural justice always apply.
But between routine government policy decisions and the traditional court forums lies a hybrid form of agency, sometimes called a "tribunal" or administrative tribunal, and not necessarily presided by judges.
These operate as a government policy-making body at times but may also exercise a licensing, certifying, approval or other adjudication authority which is "judicial" because it directly affects the legal rights of a person.
Some law teachers suggest that there is no such thing as a "quasi-judicial" decision or body. As in "quasi-pregnant", the body or decision is either judicial or not.
French: quasi-judiciaire.