Several of Australia's top climate change scientists at the Australian National University have been subjected to a campaign of death threats, forcing the university to tighten security.

Several of the scientists in Canberra have been moved to a more secure location after receiving the threats over their research.

Vice-chancellor Professor Ian Young says the scientists have received large numbers of emails, including death threats and abusive phone calls, threatening to attack the academics in the street if they continue their research.

He says it has been happening for the past six months and the situation has worsened significantly in recent weeks.

"Obviously climate research is an emotive issue at the present time," he said.

"These are issues where we should have a logical public debate and it's completely intolerable that people be subjected to this sort of abuse and to threats like this.

"I think it is totally outrageous and the vast majority of Australians would think it is totally unacceptable for anybody in society to be subjected to this sort of behaviour."

Professor Young says the outrageous behaviour has left the scientists shaken.

"Academics and scientists are actually really not equipped to be treated in this way," he said.

"The whole scientific process is one of open debate and discussion, but the concept that you would be threatened for your scientific views and work is something that is completely foreign to them."

He says the climate change issue is emotive, but all the key players should take a breath and debate the issue calmly.

The Australian Federal Police says it is aware of the issue, but there is no investigation underway.

UPDATE (June 4 2012): Following the release of specific emails under Freedom of Information request, climate change sceptics have claimed that the released emails contradict suggestions that any death threats were received, but a spokesperson for the ANU says the university is standing by its claims that death threats were received. Questions have also been raised about whether one of the released emails did, in fact, constitute a threat to use a gun, with a person involved in the kangaroo culling program claiming the comments were made by him, and were in no way intended as a threat. The specific emails released under FOI were found by the Privacy Commissioner to contain abuse, but not overt threats.