SYDNEY (AFP) - Australia opposes United States presidential candidate Donald Trump's suggestion that Japan and South Korea should develop nuclear weapons, since this would "add considerably" to the risk of regional conflict, Australian Prime Minister Malcolm Turnbull said on Sunday (April 3).

The Republican presidential front-runner had declared he would withdraw US troops from both countries and allow them to develop their own nuclear arsenals.

But Mr Turnbull said regional power Australia, a US ally, was "opposed to the further proliferation of nuclear weapons".

"That is absolutely not the view of Australia," the Prime Minister told Sky News of Mr Trump's nuclear policy comments.

"We would not support, in fact we would strenuously oppose, I think, as a global community, the further proliferation of nuclear weapons.

"Clearly... it would add considerably to tensions and the risk of conflict in the region."

South Korea and Japan last week offered muted reactions to Mr Trump's comments. There are nearly 30,000 US troops permanently stationed in South Korea and 47,000 in Japan, with little appetite for nuclear weapons in either nations.

The White House on Friday said Mr Trump's policy would shatter doctrine held for decades with "catastrophic" consequences.

Mr Turnbull in February unveiled a major new investment in Australia's defence capabilities.