Britain's former prince Andrew is under renewed pressure to answer US lawmakers' questions in Congress about Jeffrey Epstein after the US Justice Department released the latest batch of files on the case Friday.

It included embarrassing photographs of Andrew and emails between him and Epstein from 2010, two years after the financier had pleaded guilty in Florida to soliciting a minor for prostitution.

The undated photos of the then-prince show him kneeling on all fours over a woman lying on the floor.

Asked Saturday whether Andrew should testify in the US Congress as repeatedly demanded, Starmer said "yes" as he wrapped up an official visit to China and Japan.

"I've always said anybody that [has] got information should be prepared to share that information in whatever form they are asked to do that," the British leader told reporters.

US lawmakers and investigators have for years repeatedly requested he face questions about his Epstein association.

But Andrew has given no public indication in recent years that he would be willing to do so. (AFP)