Some of Australia’s most senior Liberals have leapt to defend former NSW premier Gladys Berejilkian, a day after the NSW integrity watchdog found she acted corruptly.

Federal Opposition Leader Peter Dutton launched a staunch defence of his former state counterpart on Friday, a day after the NSW integrity watchdog found Ms Berejiklian acted corruptly while in a secret relationship with fellow MP Daryl Maguire.

Mr Dutton said the findings of the NSW Independent Commission Against Corruption did not reflect the “wonderful person” he knew, dismissing the years-long integrity probe as the result of a bad relationship.

“She chose a bum, basically, and he was a bad guy,” he told Nine’s Today show.

“For that, she has paid a big price. Her integrity is not in question. She’s not a corrupt person.”

The ICAC’s 688-page, released on Thursday, found Ms Berejiklian breached the public trust by repeatedly failing to disclose her romance with Mr Maguire while taking part in more than $20 million in funding decisions for projects in his electorate.

Mr Maguire now faces criminal charges for running corrupt schemes from his office in parliament.

No charges were recommended against Ms Berejiklian, despite the findings.

Former federal Treasurer and ambassador to the US, Joe Hockey, also backed his former Liberal Party colleague. On Friday, Mr Hockey blasted the ICAC as a failure, and labelled its findings ridiculous.

“Gladys is the most honest, hard-working premier NSW has had,” he tweeted.

“She is only guilty of picking a dud.”

Tweet from @JoeHockey

NSW Liberal frontbencher and Berejiklian ally Matt Kean said he accepted Ms Berejiklian’s lack of disclosure was a breach of the ministerial code of conduct and therefore corrupt conduct under the ICAC act.

But the findings would not puncture his support of his former leader.

“I certainly believe Gladys and I continue to believe Gladys,” he told ABC TV.

On Thursday, Mr Kean also took aim at Ms Berejiklian’s choice of partner.

“The ICAC has basically revealed to us that Gladys was in a secret relationship with a weirdo,” he said.

The NSW Liberals have confirmed to the Nine newspapers that Ms Berejiklian will face no disciplinary action over the findings.

Also on Friday, NSW Premier Chris Minns refused to say whether he believed Ms Berejiklian acted corruptly. Asked if he accepted the findings, the state Labor leader said: “I’m not prepared to make that claim.”

“It’s not for me to pass judgment about findings made by independent organisations or investigatory bodies like the ICAC,” Mr Minns said.

“What I would say, and what I said about premier Berejiklian yesterday, is that I thought her service to the state during COVID was exemplary.”

The ICAC report made 18 recommendations seeking to address “systemic weaknesses” in the ministerial code of conduct, including explicitly addressing side hustles that formed the basis of the damning findings against Mr Maguire.

“The ultimate goal is to improve and enhance the reputation of the NSW parliamentary system to the betterment of the people of the state,” it read.

ICAC has urged the NSW parliament to develop a comprehensive set of principles of conduct and descriptors to guide decision-making based on the values of public trust, public interest and public duty.

This requires “detailed guidelines and clear processes to assist them to navigate ethical challenges involving conflicts of interest”.

• Can ‘gold-medal Gladys’ ever remove stain of corruption?

Griffith University public policy and law professor A J Brown said improper and unlawful conduct by MPs was a particular problem in NSW.

“The extent of the greyness of the principles and rules of parliamentarians having outside business and personal interests, giving rise to conflicts of interest, goes to the heart of this (Berejiklian) case,” he said.

“In NSW, it has been regarded as acceptable.”

Ms Berejiklian gave evidence to the inquiry that she believed she was not required to follow the ministerial code of conduct because a premier was not a minister.

Professor Brown said while Mr Maguire had no sense of any boundary between holding office and his own personal interest, there were legitimate businesses MPs engaged with that compromised their ability to perform as elected officials.

The Transparency International Australia board member said there must be the presumption that this was unacceptable, and MPs who moonlighted or held secondary employment would need a very good reason to do so.

“Too many parliamentarians don’t understand there is a dividing line once you take on the role,” he said.

Ms Berejiklian is considering her legal options to challenge the ICAC findings, maintaining she has always worked in the public interest.

“Nothing in this report demonstrates otherwise,” she said in a statement.

-with AAP