A Liberal National Party candidate has stepped aside as his party investigates an email in which he allegedly said he hopes Prime Minister Julia Gillard "follows the history" of assassinated US president John F Kennedy.

LNP state director Michael O'Dwyer on Friday evening confirmed the party's candidate for the state seat of Cairns, Paul Freebody, had voluntarily stepped aside while the party conducts an investigation into the email.

Mr Freebody denied writing the reference to president Kennedy, who was assassinated in 1963, and claimed the email - which has been circulating in far north Queensland - had been doctored.

An email obtained by AAP shows Mr Freebody also labelled Ms Gillard "evil".

"I see Gillard and Brown as the most evil people we have ever had in power in our country," the email states.

"We can only hope that she follows the history of JFK."

The email was sent to dozens of recipients and appears to have been written in reply to a circulating petition which criticises Rupert Murdoch's influence over the government.

However, Mr Freebody on Friday sent AAP a different version of the email with the letters KMR, apparently referring to Kevin Rudd, taking the place of the reference to JFK.

"Categorically, I never said that. I said she should get the same treatment she gave Kevin Rudd," he said.

Two other recipients of the email have confirmed to AAP that they received the version with the reference to "JFK" from Mr Freebody.

Senior Federal Government Minister Tony Burke says Mr Freebody should be brought to account.

Mr Burke says if the allegations are true, he is appalled.

"I just hope it is not true, I would hate to think Australian politics has gone to that sort of level," he said.

"I really hope with all the aggression that can be around in Australian politics, I hope the Liberal National Party hasn't gone to that length."

The ABC has made several attempts to contact Mr Freebody for comment.

The LNP says it will not comment until its investigation is completed.

ABC/AAP

