Former Defence secretary Paul Barratt also cautioned against parroting "shrill" anti-China rhetoric being spouted by the Trump administration.

"Naval exercises in the South China Sea are highly provocative and would simply do more harm than good. Now is not the time for antagonism," Mr Barratt said on Friday.

"A miscalculation during exercises could easily lead to armed conflict which is in no one's interests."

Australia and the United States agreed to work together more closely this week in response to China's militarisation and misbehaviour.

Australia's defence minister resisted a direct request to conduct joint patrols in the South China Sea, but said the navy would continue holding freedom of navigation operations through the contested waters.

Mr Barratt has penned an open letter to the prime minister, urging him to help lower the temperature in the increasingly bitter dispute between the US and China.

"The international community does have several valid issues with China's actions in these disputed regions, but megaphone diplomacy and risky naval exercises in contested waters will simply inflame tensions," he said.

"President Trump's increasingly bellicose and often racist comments on the issue appear more designed to appeal to a segment of the US electorate than to address the conflict in any effective way."

Australian Associated Press