Australia will discuss potential further troop increases to Afghanistan with the United States in the wake of President Donald Trump's speech announcing a new strategy for the war-torn nation, Defence Minister Marise Payne has said.

But Senator Payne has stressed that Australia is currently making a "significant contribution" to operation in the Middle East and in its own neighbourhood and has already committed to raise troop levels in Afghanistan from 270 to 300.

However, Mr Trump said when announcing his new approach that the US will ask allies and partners to "support our new strategy with additional troop and funding increases in line with our own".

US media have reported Mr Trump will increase American troops by 4000 – a rise of nearly 50 per cent on the roughly 8400 US forces there now.