Former prime minister Paul Keating has rounded on President-elect Donald Trump's secretary of state nominee, accusing him of threatening to bring on war with China and making "ludicrous" comments on the tense South China Sea dispute.

In a statement released on Friday, Mr Keating warned the Australian government to reject Rex Tillerson's declaration this week that a "signal" needed to be sent to Beijing that the construction of artificial islands in the contested region must stop and "access to those islands also is not going to be allowed".

The remarks from the former chief of Exxon Mobil, in which he also called for regional allies "to show backup", have set the stage for sharply increased tensions between the US and China as the Asian superpower builds up its military presence on the islands to defend against competing territorial claims from neighbouring countries.

According to Mr Keating, Mr Tillerson's testimony to his US Senate confirmation hearing "threatens to involve Australia in war with China". And he has urged the Australian people to "take note" and recommended the government tell the Trump administration, which will take over on January 20, "that Australia will not be part of such adventurism, just as we should have done in Iraq 15 years ago".