Washington | President Donald Trump’s plan to impose 25 per cent tariffs on steel and aluminium imports has been branded an “insult” to the Australian people and America’s key security partner in the Indo-Pacific.

Democratic congressman Joe Courtney, who co-chairs the Friends of Australia Congressional Caucus, singled out Australian taxpayers’ pumping of $US3 billion into US shipbuilding capabilities as part of the AUKUS defence pact, the first $US500 million of which was paid last week.