An Australian human rights lawyer has been angered by comments made by US vice-president Joe Biden, in which he described Julian Assange as being more terrorist than whistleblower.

The remarks also prompted Kellie Tranter to accuse Prime Minister Julia Gillard of standing by while an ally takes away Mr Assange's presumption of innocence.

In a weekend television interview Mr Biden confirmed the US government was trying to find a way to charge the WikiLeaks founder with espionage for his part in the release of thousands of secret US diplomatic cables.

But Ms Tranter says it is still unclear if Mr Assange can be charged.

"At this stage, it appears from an objective observer's point of view that Assange has not broken any law," she said.

"And if he had, you can bet your boots that the US would have put the extradition process in train."

Late last week an investigation by the Australian Federal Police found Mr Assange had not broken any Australian laws.

That is despite Ms Gillard having previously described his actions as illegal.

After the AFP announced its finding, Ms Gillard was talking up efforts to charge Mr Assange under US law.

Ms Tranter says both Ms Gillard and Mr Biden are denying Mr Assange his presumption of innocence.

"Joe Biden's comments are utterly unacceptable, and I think Prime Minister Gillard should be objecting to them having been made in relation to an Australian national, particularly when we've already heard calls for Mr Assange's assassination," she said.

"So this is not behaviour we would expect of an ally towards one of our own."

Mr Assange is out on bail in Britain and is fighting extradition to Sweden on sex assault charges.

Late last week, Mr Biden said there had been no substantive damage to US foreign policy since the release of diplomatic cables by WikiLeaks.

But he has confirmed the US government is actively trying to find a way of charging Mr Assange with espionage.

"We're looking at that right now. The justice department is taking a look at that and I'm not going to comment on that process," he said.

When asked whether he thought Mr Assange was a high-tech terrorist or a whistleblower akin to those who released the Pentagon Papers - a series of top-secret documents revealing US military policy in Vietnam - Mr Biden said: "I would argue that it's closer to being a high-tech terrorist."