Australia plans to acquire a fleet of cutting-edge, nuclear-powered submarines under AUKUS, a multi-decade defence pact with Britain and the United States.

As part of the deal, Australia will build some of the new class of SSN-AUKUS submarines for delivery in the early 2040s, though the reactors will still be built in Britain.

"We've just spent Aus$310 million ($220 million) acquiring the very first parts that will go into the reactors for the first two submarines that we will construct in Adelaide beginning later this decade," Australian Defence Industry Minister Pat Conroy said after meetings in Britain.

"This project will create 20,000 high-skilled, secure jobs making the most advanced submarines in the world, equipping the Royal Australian Navy with the capabilities it needs to deter conflict in our region."

Under AUKUS, the Australian navy aims to acquire at least three US Virginia-class nuclear-powered submarines within 15 years as part of a strategy to counter China's military in the Pacific.

Britain would then develop the new SSN-AUKUS for delivery in the late 2030s.

Australia would also construct the vessel to go into service in the early 2040s, but remain reliant on Britain for the delivery of complete, welded nuclear propulsion units.

The latest payment is in addition to Aus$2.4 billion Australia is paying over 10 years to expand the production capacity of Rolls-Royce Submarines, the government said.