Australia is in the midst of a major military restructuring announced in 2023, turning towards long-range strike capabilities to better respond to China's naval might.

It is striving to expand its fleet of major warships from 11 to 26 over the next 10 years.

"This is clearly the biggest defence-industry agreement that has ever been struck between Japan and Australia," Marles said, touting the US$6 billion (Aus$10 billion) deal.

Mitsubishi Heavy Industries was awarded the tender over Germany's ThyssenKrupp Marine Systems.

"This decision was made based on what was the best capability for Australia," Marles said.

"We do have a very close strategic alignment with Japan."

Mogami-class warships are advanced stealth frigates equipped with a potent array of weapons.

Marles said they would replace Australia's ageing fleet of Anzac-class vessels, with the first Mogami-class ship to be in service by 2030.

"The Mogami-class frigate is the best frigate for Australia," said Marles.

"It is a next-generation vessel. It is stealthy. It has 32 vertical launch cells capable of launching long-range missiles."

Defence industry minister Pat Conroy said the frigates were capable of launching long-range Tomahawk cruise missiles.

- 'More lethal' -

"The acquisition of these stealth frigates will make our navy a bigger navy, and a more lethal navy," he said.

The first three Mogami-class frigates will be built overseas, Conroy said, with shipbuilding yards in Western Australia expected to produce the rest.

Australia announced a deal to acquire US-designed nuclear-powered submarines in 2021, scrapping a years-long plan to develop non-nuclear subs from France.

Under the tripartite AUKUS pact with the United States and the United Kingdom, the Australian navy plans to acquire at least three Virginia-class submarines within 15 years.

The AUKUS submarine programme alone could cost the country up to US$235 billion over the next 30 years, according to Australian government forecasts, a price tag that has stoked criticism of the strategy.

Major defence projects in Australia have long suffered from cost overruns, government U-turns, policy changes and project plans that make more sense for local job creation than defence.

Australia plans to gradually increase its defence spending to 2.4 percent of gross domestic product -- above the two percent target set by its NATO allies, but well short of US demands for 3.5 percent.