US President Donald Trump on Wednesday withdrew his chief strategist, Steve Bannon, from the National Security Council on Wednesday after it was decided he was no longer needed on the key foreign policy group, a senior White House official said.

Bannon's removal from the NSC, which includes senior members of Trump's foreign policy team, was seen as a boost to national security adviser HR McMaster, who officials said has struggled to work together with Bannon.

A senior White House official, speaking on condition of anonymity, said Bannon's presence on the NSC was no longer needed after the departure of Trump's first national security adviser, Michael Flynn.

Flynn was forced to resign in February over his contacts with Russia's ambassador to the United States, Sergei Kisylak, prior to Trump's taking office on Jan 20.

The official said Bannon had been placed on the NSC originally as a check on Flynn and had only ever attended one of the NSC's regular meetings.