Donald Trump's former lawyer Michael Cohen has postponed testimony in Congress citing threats from Trump and the president's current attorney Rudy Giuliani, Cohen's advocate said on Wednesday.

Cohen's appearance before the House Oversight Committee, scheduled for February 7, was put off "due to ongoing threats against his family from President Trump and Mr Giuliani, as recently as this weekend," Lanny Davis said in statement.

"This is a time where Mr Cohen had to put his family and their safety first," Davis added.