WA Labor candidate Anne Aly claims she's the victim of a smear campaign

Labor's candidate for Cowan says she is the victim of a smear campaign as her leader demanded the PM call off the attack dogs over a divisive preacher.

File image of Anne Aly outside Labor headquarters in WA Source: SBS

Labor's candidate for the marginal seat of Cowan and counter-terrorism expert Anne Aly said on Thursday she's the victim of a despicable smear campaign as the opposition demand Prime Minister Malcolm Turnbull call off the "attack dogs".

Justice Minister Michael Keenan on Thursday said Dr Aly showed poor judgment by helping a controversial self-styled Islamic preacher have his jail sentence reduced.

Junaid Thorne, who flew domestically under a fake name, had his term cut to a minimum of four months last year after tendering a letter of support from Dr Aly to the NSW District Court.

"I think that shows pretty poor judgment," Mr Keenan told ABC radio in Perth.

He conceded the federal government had funded Dr Aly's early intervention and deradicalisation program but said the government had not funded her to provide letters of support for known hate preachers and convicted criminals.

Thorne, a 27-year-old preacher, has previously expressed his support for the Charlie Hebdo attack in Paris and slain teen terror suspect Numan Haider.

Foreign minister Julie Bishop weighed in on the debate on Friday, throwing her support behind Mr Keenan.

"She did write a letter for a known hate preacher ... in an attempt to get him off jail time," she said.

"That is not part of the role the federal government was funding her for."

Ms Bishop also said Ms Aly was "not supporting a number of national security efforts" and this is was pattern across the Labor party. 

"We now see there are about 50 Labor members and candidates who disagree with Bill Shorten when he backs the Turnbull government’s approach to border protection."

Dr Aly, who founded the body People Against Violent Extremism, said the government had supported her deradicalisation work.

"Ministers have applauded the work that I do and suddenly now, at the pointy end of an election, the minister for justice turns around and tries this pretty despicable smear campaign," she said.

Her submission on Thorne's behalf outlined deterrence proposals aimed at keeping him and his co-accused, Mostafa Shiddiquzzaman, on the right side of the law, she added.

"They were not arrested or detained under terrorism laws so it had nothing to do with them being radicalised at all," she said, adding she had a very good working relationship with the Attorney-General's department.

Mr Turnbull said he could not comment on reports he had not seen, but Labor leader Bill Shorten demanded he call off the "attack dogs", saying it was a "desperate smear".

Mr Shorten said Dr Aly was so well-respected in her field she was invited to advise the White House.

She had also been put on extremist group kill lists because of her work, he said.

Foreign minister Julie Bishop weighed into the furore.

"I understand that she provided some kind of support for someone who is of great interest to our security, intelligence and law enforcement agencies, and it would be a matter for her to explain why she did that," Ms Bishop said.