Donald Trump has embarked on an unprecedented purge of government officials appointed by President Barack Obama in a bid to wipe the slate clean ahead of his inauguration.

Scores of presidential appointees, from ambassadors in far flung capitols to two nuclear security chiefs to the head of Washington's National Guard, will be leaving their posts on Friday at noon, having received unexpected orders to do so, just as Trump takes office as one of the most unpopular and scandal-ridden incoming presidents in history.

While his recent predecessors were swept toward inauguration day on a tide of goodwill, Mr Trump has jolted from scandal to intrigue and back again, lashing out at his critics on Twitter and rarely appearing in public.

Just 44 per cent of Americans approve of how he has handled his transition to the presidency, compared to 83 per cent for Barack Obama, 61 per cent for George W Bush and 68 per cent for Bill Clinton, according to Gallup.