Donald Trump has hit out at US Supreme Court justice Ruth Bader Ginsburg by telling her to resign after she called him "a faker".

Ginsburg, who has been a member of the US Supreme Court for more than 23 years, told CNN she thought the press had been gentle on Trump over his tax returns, following up from comments she made earlier in the week about his suitability for the role of president.

"He is a faker," she told the news outlet. "He has no consistency about him. He says whatever comes into his head at the moment. He really has an ego... How has he gotten away with not turning over his tax returns? The press seems to be very gentle with him on that."

On 11 July, Ginsberg had told The New York Times: "I can't imagine what this place would be, I can't imagine what the country would be, with Donald Trump as our president."

Trump, who has had several high-profile spats with both political figures and journalists, among others, hit back at Ginsberg and suggested justices should remain apolitical ahead of the presidential election.

He tweeted: "Justice Ginsburg of the US Supreme Court has embarrassed all by making very dumb political statements about me. Her mind is shot − resign!"

He also responded to The New York Times over Ginsberg's comments telling them he thought it was "highly inappropriate" that she was involved in commenting on political campaigns and stating she should apologise to the Supreme Court.