Labor has sounded a clear warning to United States President Donald Trump that he cannot afford to corrode alliances with like-minded democracies, saying a "global rethink" about how to work with the superpower is already underway.

The party’s foreign affairs spokeswoman Penny Wong has also called for the Turnbull government to establish an infrastructure investment fund dedicated to the Pacific region.

Senator Wong told the United States Studies Centre at Sydney University on Wednesday night that Mr Trump’s ditching of international agreements and his punitive trade measures against US allies was nothing less than a rejection of international rules and norms.

“The global community is still coming to terms with this new America,” she said. “The reconfigured way the US is setting about conducting itself in the management of global affairs is generating something of a global rethink about how best to work with the US.”