Australia's oldest ally has vowed to challenge Beijing's territorial claims in the South China Sea by sailing two new aircraft carriers through the disputed waterways on a freedom-of-navigation operation.

Key points: Initial deployments have not been mapped out yet, Michael Fallon says

Initial deployments have not been mapped out yet, Michael Fallon says US, Australia and Britain have long expressed concerns with Beijing's activity

US, Australia and Britain have long expressed concerns with Beijing's activity Marise Payne hints Australia could assert freedom of navigation in South China Sea.

British Foreign Secretary Boris Johnson has confirmed the move following a high-level meeting in Sydney with his Australian counterpart Julie Bishop, as well as the Defence Ministers from both nations.

"One of the first things we will do with the two new colossal aircraft carriers that we have just built is send them on a freedom-of-navigation operation to this area to vindicate our belief in the rules-based international system and in the freedom of navigation through those waterways which are absolutely vital for world trade," Mr Johnson said.

What 'colossal aircraft carriers'? The warships Boris Johnson refers to are the UK's newest aircraft carriers, the HMS Queen Elizabeth and HMS Prince of Wales

The warships Boris Johnson refers to are the UK's newest aircraft carriers, the and At 280 metres and 65,000 tonnes, the HMS Queen Elizabeth is the largest ship ever built for the Royal Navy

At 280 metres and 65,000 tonnes, the HMS Queen Elizabeth is the largest ship ever built for the Royal Navy The second ship in the class, the HMS Prince of Wales is being fitted out in Scotland and will be officially named in September

The second ship in the class, the HMS Prince of Wales is being fitted out in Scotland and will be officially named in September Both ships are capable of carrying up to 40 aircraft

On the ABC's 7.30 program, British Defence Secretary Sir Michael Fallon declined to give details of the impending deployment.

"We haven't mapped out the initial deployments yet but, yes, you would expect to see these carriers in the India Pacific Ocean, this part of the world because it is in this part of the world we see increasing tension, increasing challenges," he said.

The United States and close allies, such as Australia and Britain, have long expressed concerns with Beijing's island-building activity and militarisation of one of the busiest commercial sea routes in the world.

Boris Johnson (L to R) confirmed the move following a meeting with his Australian counterpart Julie Bishop, as well as Marise Payne and Michael Fallon. ( ABC News: Siobhan Fogarty )

Defence Minister Marise Payne has hinted Australia could also play a role alongside Britain in asserting freedom of navigation in the South China Sea.

Why China won't play ball China's interests in relation to North Korea are fundamentally different from ours, and no matter how much we cajole or threaten, it will not act the way we want it to. Read more Read more

"Importantly today, we also discussed developments in our region, particularly with respect to freedom of navigation and freedom of overflight which is a global issue and countries like Australia and the United Kingdom have a shared interest in those global freedoms," Senator Payne said on Thursday.

"We agreed today that we would identify opportunities to conduct, where possible, cooperative activities in the region when we have assets that are in the area at the same time."

The ABC revealed last week the Australian Defence Force had detected a Chinese spy ship close to the Queensland coast during joint military exercises with the US, known as Talisman Sabre.

On Thursday, the visiting Commander of the US Pacific Fleet told the ABC he was not bothered by China's actions during the exercises, but hoped it would reinforce to Beijing the importance of the United Nations Convention on the Law of the Sea.

"It appears to be two different approaches taken on the part of China. They express great umbrage at United States military operations that are conducted within their EEZ [Exclusive Economic Zone]," Admiral Scott Swift said.