Scott Morrison’s attacks on NSW’s ICAC and endorsement of embattled former premier Gladys Berejiklian to join federal politics have intensified, with the Prime Minister saying she would be a “great” candidate, despite an ongoing corruption investigation.

Senior Liberals are escalating their public calls for Ms Berejiklian to switch from NSW politics to Canberra – despite a cloud hanging over her knowledge of corruption by ex-boyfriend Daryl Maguire – in the face of a huge community campaign from Warringah incumbent Zali Steggall.

And even as the federal government stalls its plans for a Commonwealth integrity body, Mr Morrison has again attacked the NSW anti-corruption watchdog, hinting that an adverse finding against Ms Berejiklian wouldn’t scupper any bid for high office.

“I think she would be great. The way that Gladys Berejiklian has been treated has been shameful,” PM Morrison said on Monday.

Ms Berejiklian gives evidence to ICAC in October.

“I don’t call that justice.”

Ms Berejiklian voluntarily quit as NSW Premier, due to conditions she set out in her own ministerial code, after the Independent Commission Against Corruption announced it was investigating her conduct. ICAC is probing whether she breached public trust in a partial or dishonest exercise of her office by promising funding to ventures Mr Maguire had an interest in, or if she allowed or failed to report concerns of corrupt activity by Mr Maguire.

The ICAC investigation has not reported its findings yet. But Mr Morrison and other senior members of his government have publicly encouraged Ms Berejiklian to run for the federal seat of Warringah. It was formerly held by ex-PM Tony Abbott, before he was defeated by independent Ms Steggall in 2019.

The Sydney Morning Herald on Monday quoted a so-called “senior Liberal” saying “the feds clearly don’t care” about the active corruption probe. In morning interviews, Finance Minister Simon Birmingham and Environment Minister Sussan Ley both said they would “love to see” Ms Berejiklian join federal politics,.

Ms Ley described the ICAC process as a “public shaming” of an “outstanding representative”. Senator Birmingham claimed it was “pretty sad when ICACs go out and destroy reputations, do so in pretty murky ways”.

Mr Morrison has been strongly critical of the NSW integrity body, describing it as a “kangaroo court”. On Monday, he claimed Ms Berejiklian had been subject to a “pile-on”.

“If she wished to join our team, she would be very welcome,” he said at a press conference, from a school in Sydney’s east.

Mr Morrison. Photo: AAP

Mr Morrison complained that Ms Berejiklian was “put in a position of actually having to stand down and there was no findings of anything”, and that there was “no suggestion of criminal conduct”.

In fact, Ms Berejiklian was clear in her resignation statement that she was voluntarily resigning, due to conditions she put in her own ministerial code for NSW government ministers. ICAC never publicly accused Ms Berejiklian of criminal conduct, only outlining investigations of her actions specifically in relation to Mr Maguire.

ICAC might not hand down its findings into Ms Berejiklian until early 2022. She has not been cleared of wrongdoing.

“If she wants to have a crack at Warringah for the Liberal Party, I suspect the people would welcome that in Warringah,” Mr Morrison said.

“We will let the people decide.”

Online petitions calling for Ms Berejiklian to be reinstated as NSW premier garnered tens of thousands of signatures.

Liberal pre-selection for Warringah has been extended until January, reportedly to allow Ms Berejiklian more time to consider her future.

However, her potential entry as a federal candidate would likely supercharge a Commonwealth anti-corruption body as a national election issue, further exposing the Coalition’s failure to legislate such a body nearly 1100 days after first proposing one.

Labor frontbencher Chris Bowen, speaking at the National Press Club, said the government would not “get a leave pass” from the opposition on the issue. He called Mr Morrison’s criticisms of ICAC “disgusting” and claimed the PM had “undermined” the body with his comments.

Ms Steggall won Warringah in 2019 by a 57-43 two-party margin over Mr Abbott. As the Liberals continued courting Ms Berejiklian, Ms Steggall launched her volunteer campaign on Sunday, with hundreds of locals massing in her signature turquoise T-shirts.

Tweet from @zalisteggall

Under a slogan of “catch the new wave”, Ms Steggall assembled more than 300 volunteers who will underpin her ground game through the election campaign, following a huge community groundswell of support in 2019.

Ms Steggall’s office declined to comment on the ongoing interest around the Liberal candidate who would challenge her on election day.