The editor-in-chief of The Australian is threatening to sue a journalism academic over claims published on Twitter that he told a staff member what to write in regards to the paper's coverage of climate change.

In an article published on The Australian's website, Chris Mitchell says he will sue Julie Posetti for defamation because of tweets she made purporting to quote a former rural reporter for The Australian.

Ms Posetti tweeted alleged quotes made yesterday by Asa Walhquist at a journalism conference at the University of Technology, Sydney.

Ms Posetti posted: "Walhquist: 'In the lead up to the election the Ed in Chief was increasingly telling me what to write.' It was prescriptive."

In another tweet Ms Posetti claims Walhquist said: "'It was absolutely excruciating. It was torture': Asa Walhquist on fleeing The Australian after being stymied in covering #climate."

In The Australian's article published on Friday, Mitchell has rejected the allegations and says Walhquist has also denied to him she made the comments.

"Asa may or may not have said what the tweeter alleges. She denies to me that she did. But either way the allegations are a lie and Asa has admitted as much," he said.

"There is not protection from the law in repeating accurately allegations falsely made. Asa works from home and I have neither seen her nor spoken to her in years, as anyone on the paper would attest."

Mitchell says he contacted Walhquist after the tweets were made and he sent her an email saying he had "never spoken" to her about any of her stories.

"Indeed, I have not spoken to you in at least eight years. And I have never stood over people writing stories in 19 years as an editor," he said.

Mitchell says he will sue Ms Posetti because he believes new media should not be exempt from the "normal laws of the land".

Ms Posetti says she is "seeking advice" before making further comment.

The ABC understands Ms Posetti has not been asked to correct or withdraw the comments.

Geoff Elliott, the editor of The Australian's media section, says he has left messages for Ms Posetti.

It is believed audio of the journalism conference exists, however the ABC has not heard it.

Ms Posetti is a journalism lecturer at the University of Canberra and a former ABC journalist who worked as a Canberra political correspondent.

ABC News Online has sought comment from Asa Walhquist.