Julian Assange's biological father has claimed the Australian activist will be murdered if he is extradited to the United States.

Assange father John Shipton claimed his son is in danger after the UK government cleared the way for his extradition to the US where he faces computer hacking charges.

Assange, who spent almost seven years in the Ecuadorean embassy, was due to be released from prison last Friday, but was remanded in continuing custody until his extradition hearing in February.

John Shipton, Julian Assange's biological father, pictured, is fearful his son will be 'murdered' if sent to face trial in the United States on computer hacking charges

Assange was arrested in April after the Ecuadorean embassy told the Metropolitan Police that they were no longer offering asylum to the Australian Wikileaks founder

Assange, 48, was jailed in June to serve a 50-week jail term, almost seven years after he sought asylum in the Ecuadorean embassy to avoid extradition to Sweden where he wanted in connection with sexual offence allegations.

The Australian was due to be released from prison on September 22, but he now faces extradition to the United States to face computer hacking allegations.

The then Home Secretary Sajid Javid signed an order in June allowing the extradition.

His extradition hearing is not due to be heard until February 2020, however he is being held in custody because of his 'history of absconding'.

District Judge Vanessa Baraitser told him last Friday: 'You have been produced today because your sentence of imprisonment is about to come to an end.

'When that happens your remand status changes from a serving prisoner to a person facing extradition.

Then Home Secretary Sajid Javid, pictured, announced he would authorise Assange's extradition to the United States pending a hearing at Westminster Magistrates's Court

'Therefore I have given your lawyer an opportunity to make an application for bail on your behalf and she has declined to do so. Perhaps not surprisingly in light of your history of absconding in these proceedings.

'In my view I have substantial ground for believing if I release you, you will abscond again.'

Assange's father John Shipton criticised the decision to hold his son in custody.

In an interview with the Strategic Culture Foundation, Mr Shipton said: 'Julian has lost 15 kilos in weight, is held in Belmarsh Maximum Security prison hospital 22 hours per day in solitary confinement.'

Mr Shipton claimed Assange was being denied proper visits and access to his legal team.

He also said: 'They will murder Julian one way or the other.'