New fleet of 12 offshore patrol boats to be built for the navy in Adelaide from 2018, PM announces

A new fleet of 12 offshore patrol boats will be built for the navy in Adelaide from 2018, Prime Minister Malcolm Turnbull has announced.

They will replace the smaller Armidale-class vessels which were built in Western Australia.

The building program will be transferred to WA when Adelaide begins work on the navy's future frigates in 2020.

As well, Austal Ships will construct and maintain up to 21 replacement steel-hulled Pacific Patrol Boats at its Henderson shipyards in WA.

With the Future Frigates build the government will invest $40 billion in the three projects.

Mr Turnbull said 2500 jobs would be created over the time of the building programs.

"These are very important announcements concerning the future of our nation, the future of our security and the future of our modern navy," Mr Turnbull told reporters in Canberra.

The government's great endeavour was to re-equip the navy and naval ship building industry, he said.