In Australia, a justice of the peace is a volunteer, a member of the community who plays a key role in the administration of justice and who is not paid for it.

A JP can witness signatures on legal declarations, certify that copies of documents are a true and exact copy of the original, can issue citations and police search warrants. A JP is one of the short categories of people who can witness the bride and groom’s signatures on the Notice of Intended Marriage, the document that, in Australia, a couple must present with their marriage celebrant (wedding officer) or clergy . person a minimum of one full month before the wedding can take place. This document serves the same purpose as the marriage license required in many other countries.

All marriage celebrants and clerics licensed to perform marriages (not all clerics are licensed to perform marriages) may also witness their signatures on the Notice. Generally speaking, an Australian JP will be asked to witness signings where the couple is making arrangements for a remote destination wedding and it is therefore not possible or convenient to meet the chosen celebrant for this purpose.

what JP can not do, is to perform the actual marriage ceremony.

There are a number of reasons for this.

• History and Tradition: Historically, marriage ceremonies have been performed only by persons authorized under the Marriage Act, including clergy, marriage officers attached to each Register of Births, Deaths, and Marriages, and, since 1973, Celebrants of Civil marriage appointed by the Australian Attorney General.
• In Australia, marriage falls under the jurisdiction of the Commonwealth because the Marriage Act is a Federal Law. Justices of the peace, however, are appointed by each State.

The celebrant of your civil marriage can witness the legal declarations related to your marriage and, in fact, must witness the Declarations that must be made on the back of the official marriage certificate stating that you are free to marry.