Rectification of errors apparent on the face of record permits correction of official documents subject to natural justice. Any authority that issued a decision, order, notice, certificate or other document may rectify errors apparent on the face of record on its own motion or when alerted by an authorised officer or the affected person, subject to prescribed time limits; a general six month outer limit applies but does not bar purely clerical or arithmetical corrections, and any rectification that adversely affects a person must observe the principles of natural justice.