WikiLeaks founder Julian Assange has been offered an Aboriginal Nations passport in an inner-city Sydney ceremony after he was "abandoned" by Australian authorities.

His father, John Shipton, accepted the document at a celebration in Darlington today.

WikiLeaks founder Julian Assange. Credit:Reuters

He said his son had been jilted by the Australian government, and the passport ceremony - which follows Ecuador's decision to grant Mr Assange diplomatic asylum - was a show of solidarity.

"Australian governments of every colour are happy to abandon their citizens when they're in difficult situations overseas," he said.