Presumptive Republican presidential nominee Donald Trump fired back at Supreme Court Justice Ruth Bader Ginsburg after she expressed fear over a Trump presidency in interviews.

In a tweet, Trump called Ginsburg's public statements in recent days "dumb" and said "Her mind is shot - resign!"

In interviews with the New York Times and Associated Press, Ginsburg took the unusual step for a justice of weighing in on a candidate in a presidential election year.

"I can't imagine what this place would be — I can't imagine what the country would be — with Donald Trump as our president," Ginsburg told the Times in an interview posted online on Sunday.

"For the country, it could be four years. For the court, it could be — I don't even want to contemplate that," she said, joking that her husband, who died in 2010, would have said, "'Now it's time for us to move to New Zealand.'"