The navy on Wednesday welcomed new head Vice Admiral Mark Hammond at a ceremony in Canberra.

The former chief, Vice Admiral Noonan, who has led the Australian navy for the past four years, said personnel had shown "exceptional resilience, strength and adaptability in challenging times".

"They have provided unprecedented support for the Australian community during COVID-19, the 2019-20 bushfires and recent floods, while also maintaining navy's consistent presence in the southwest Pacific and wider Indo-Pacific region," he said.

"Navy is undergoing its biggest evolution since the Second World War in order to respond to a dynamic strategic environment."

The 38-year Royal Australian Navy veteran described Vice Admiral Hammond as an "exceptional leader".

Vice Admiral Hammond said officers and sailors of the navy reflected the best of Australian society.

"They are Australians who are ready to defend Australia and its national interests in the maritime domain, and work incredibly hard to protect our maritime approaches and vital trade routes," he said.

The government has approved the navy's workforce to grow to more than 20,000 people by 2040 and announced at least eight nuclear-powered submarines would be acquired through a trilateral agreement with the UK and US.

Vice Admiral Hammond, the first graduate of the Australian Defence Force Academy to become chief of the navy, had an extensive career as a submariner and served as commanding officer of HMAS Farncomb, a Collins-class submarine.

He served as commander of the Australian fleet from 2020 and as deputy chief from 2018 to 2020.

He joined the navy in 1986 to become an electronics technician and was commissioned as an officer in 1988.

Australian Associated Press