Beijing on Thursday slammed a new US alliance with Australia and Britain, under which Canberra will acquire nuclear submarine technology, as an "extremely irresponsible" threat to regional stability.

The agreement "seriously undermines regional peace and stability and intensifies the arms race", Chinese foreign ministry spokesman Zhao Lijian told a regular press briefing.

The Western allies did not mention China when unveiling the submarine deal on Wednesday, but their intent was clear, with each referring to regional security concerns.

The announcement comes as Australia has been boosting defence spending with a wary eye on a rapidly rising and more assertive China.

The alliance is seen as a bid to offset China's growing economic and military reach in the Asia-Pacific region.

"The export of highly sensitive nuclear submarine technology by the United States and Britain to Australia once again proves that they use nuclear exports as a tool of geopolitical games and adopt double standards, which is extremely irresponsible," Zhao said.

He added that the deal gave regional countries "reason to question Australia's sincerity in abiding by its nuclear non-proliferation commitments".

He urged the Western allies to "abandon their outdated Cold War zero-sum thinking" or risk "shooting themselves in the foot".