A group of doctors has asked Foreign Minister Marise Payne to evacuate Julian Assange to an Australian hospital amid claims the WikiLeaks founder's health is rapidly deteriorating and that he "might die" in a London prison.

Detailing allegations of "psychological torture" inflicted on Assange during efforts to extradite the 48-year-old to the United States, 100 medical doctors have urged Senator Payne and Prime Minister Scott Morrison to intervene.

Assange in a police vehicle following his arrest at London’s Ecuadorian embassy in April. Credit:Getty Images

"It is an extremely serious matter for an Australian citizen’s survival to be endangered by a foreign government obstructing his human right to health," the doctors say in a letter.

"It is an even more serious matter for that citizen’s own government to refuse to intervene, against historical precedent and numerous converging lines of medical advice.