Australia will attempt to salvage what is left of the moribund Trans-Pacific Partnership after US President Donald Trump used his first full day of business to formally withdraw from the free trade deal, as he had long promised.

Prime Minister Malcolm Turnbull indicated the 11 remaining countries could look to include China as a possible replacement for the US, the world's largest economy, as he mounted a strong defence of free trade on Tuesday.

"It's a great shame [but] it's not unexpected": Trade Minister Steve Ciobo. Credit:Alex Ellinghausen

"Certainly there is the potential for China to join the TPP," Mr Turnbull said, noting he had "active discussions" with other leaders, including Japanese PM Shinzo Abe on Monday, about resuscitating the doomed trade agreement.

Stressing that Australians were more dependent on trade than Americans, the PM said other nations could "make whatever judgments they wish" but "Australian trade policy is written in Canberra in the interests of Australian jobs".