'I feel sick': Pamela Anderson visits Julian Assange in jail

US actress Pamela Anderson has urged more people to support WikiLeaks founder Julian Assange after visiting him in a London prison where he is awaiting a hearing on a US extradition request.

"He's an innocent person... He's a good man, he's an incredible person. I love him," Anderson told reporters after she and WikiLeaks editor Kristinn Hrafnsson met Assange at Belmarsh prison.

The US government has accused Australian citizen Assange, 47, of conspiring with former US military intelligence analyst Chelsea Manning to leak a trove of classified material in 2010.

He has been held at the prison since police dragged him from the Ecuadorian embassy in London on April 11. He had spent seven years inside the embassy to avoid arrest.

In a brief court appearance via video from the prison last week, Assange confirmed that he opposes his extradition. The case is expected to take up to one year to resolve.

"It's going to be a long fight... and he needs our support. He needs all the support he can get," said Anderson, 51, who befriended Assange during visits to the embassy.

"He's sacrificed so much to bring the truth out," she said, adding that she felt "sick" after meeting Assange in prison.

Hrafnsson also said it was "shocking to see my friend - an intellectual, a journalist... sitting in a high-security prison."

He said Assange had lost weight but "his spirit is strong."

"Julian Assange is bent but not broken. He is an extraordinarily resilient person," Hrafnsson added. "He knows that he has done nothing wrong."