The Public Seal is reserved for documents which require the signature of the Governor-General. These include the following categories where its use is obligatory: (a) Proclamations; (b) Crown grants (now very rare); (c) Warrants of appointment of members of the Executive Council and Ministers' warrants of appointment; (d) Appointments of the Chief Justice and of Justices of the Supreme Court; (e) Appointments of Royal Commissions; (f) Warrants for appointments to Army, Navy, and Air Force.

Documents which merely require ministerial signature are, if necessary, sealed with the common seal of the particular Department concerned.