Australian MPs Andrew Wilkie and George Christensen will visit Julian Assange in a London prison and put pressure on the Morrison government to lobby Britain and the United States for his freedom.

Accusing the government of abandoning the WikiLeaks founder, Mr Wilkie, a former intelligence official, said Mr Assange had "almost no political patronage" from Australians despite the issue becoming a high-profile one in the United Kingdom.

The unlikely political alliance of the Tasmanian independent MP and Mr Christensen, a conservative Liberal-National Party MP from north Queensland, has grown into a 14-member Parliamentary Friends of Julian Assange group.

Apart from Mr Christensen it has no other government members. Both the Coalition and Labor have been reluctant to voice public support for the Australian activist.