The RAN's oldest warship, and the only ship still driven by steam, is making her 'last hurrah' voyage.

The 4,720-tonne, heavily-armed DDG left her home port of Fleet Base East on July 2 to visit for the last time all capital cities of Australia.

She will also visit New Zealand.

"The voyage will take three months. We'll be back in Sydney in mid-September," her commanding officer, CAPT Cam Darby said.

He told of the voyage during his welcome to his ship of the VIPs attending the launch of the Admiral for a Day competition for high school children throughout NSW and the ACT (see page one story).

"This will be BRISBANE's last hurrah," he said.

Upon her return she will be readied for the Naval Review on Sydney Harbour in October.

On October 19 she is scheduled to be decommissioned.

Brisbane was built by the Defoe Shipyard in the USA and commissioned in 1967.