A multi-billion dollar submarine deal between long-standing allies - Australia, the UK and the US - has come under the spotlight after the Trump administration said it was reviewing how the deal fits in with its heavily-touted "America First" agenda.

Australian Deputy Prime Minister Richard Marles announced Thursday he feels that the AUKUS nuclear submarine deal which connects with the United Kingdom and United States, will continue after the Trump administration reviews the pact.

Congressional Democrats condemned the review as casting doubt over the strength of America's alliances with Britain and Australia.