From the previous posting you can see marriage records in Queensland since 1934 are not available for public perusal. Other states have similar restrictions. If I needed a copy of my own marriage certificate I would have to prove my identity, lodge an application, pay the required fee and have the copy mailed to me about a week later.
Vital Records - Births, Deaths, Marriages
Locate vital records including birth, death, and marriage, and adoption information.
Note: There are no agencies in Australia that provide information on current records to the general public. Many do however maintain historical indexes and information useful for genealogical research.
ACT Registrar General's Office
Provides access to birth, death, marriage, and adoption records subject to an access policy.
Department for Victorian Communities
Records the births, deaths, marriages and adoptions of people in Victoria.
Northern Territory Department of Justice
Responsible for recording all births, deaths, marriages and changes of names occurring in the Northern Territory.
NSW Registry of Births, Deaths, and Marriages
Application forms for birth, death and marriage certificates; change your name, amend details on an existing certificate, or research your family history.
Office of Consumer and Business Affairs
The Births, Deaths and Marriages Registration Office is responsible for maintaining registers of births, deaths, marriages, changes of name, adoption of children and reassignments of sex that occur in South Australia.
QLD Department of Justice and Attorney General
Keeps records of all births, deaths and marriages that have occurred in the State since 1 January 1890.
Tasmania Department of Justice
The main responsibilities of the Tasmanian Registry of Births, Deaths and Marriages are Registration of Tasmanian births, deaths, marriages and deeds of relationships, and applications for birth, death and marriage certificates.
WA Department of Justice
All births, deaths and marriages in Western Australia are recorded by the Registry of Births, Deaths & Marriages.http://www.peoplesearch.com.au/Public_Records/Vital_Records/