The Wikileaks founder has been in the Ecuadorian Embassy in London since June 2012, to avoid extradition to Sweden where he faces questioning over alleged sex assaults.

Facing arrest if he leaves the building, his mother, Christine Assange, confirmed on Friday that limited access to the outside world has had "severe" effects on his health.

She told ABC Radio on Friday his body is breaking down to such an extent he now has heart problems, a chronic lung infection, as well as deep and severe shoulder pain.

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Emergency medicine expert, Dr Stephen Parnis, believes long-term confinement may have caused Assange physical and psychological ailments.

Physical

Dr Parnis, the vice-president of the Australian Medical Association, said lack of vitamin D from sunlight and proper exercise, may cause the body to break down.

"You can de-condition relatively quickly, lose muscle bulk, lose bone-mineral density and some of your cardio respiratory fitness or aerobic fitness," Dr Parnis said.

"If you do lose bone-mineral density, it isn't easy necessarily to get that back.

"That may manifest itself in years to come with things like fractures. If you are confined indoors for a prolonged period of time, it does carry significant risk.

"People have this after prolonged hospital admissions. That’s why good rehabilitation is so important."

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Mental

Dr Parnis said a person in confinement suffered psychologically due to lack of interaction with other people.

"We are meant to move about and interact with people," he said.

"While you can do things to mitigate that, whether it be exercise, careful attention to diet, and even issues do with your psychological wellbeing... (you) still would require a transition to move back into a normal way of being."

"You can do things to mitigate some of those harms - but it isn't good for anyone to be locked away for such a long period of time."

Dr Parnis said he was amazed at the resilience Mr Assange had demonstrated and that it took a certain degree of patience, fortitude and the ability to suffer or endure things that many other people wouldn't.

It may not get any better for Mr Assange, who plans on leaving the embassy on Friday night.

British authorities have said they would arrest him if he steps foot from the embassy, despite a UN ruling that he had been arbitrarily detained.