Self-described as "by the book", Ms Berejiklian landed herself in hot water on Monday after she was forced to reveal a five-year relationship with former MP and ICAC subject Daryl Maguire.

The pair kept in contact until last month, despite Mr Maguire's fall from grace in 2018.

The premier has spent the last two days putting out fires, assuring her colleagues of her leadership and insisting she had no clue the conduct or financial dealings of her secret former boyfriend may be dodgy.

ICAC has accused Mr Maguire of using his public office to improperly gain a benefit for himself or for G8way International, a company he allegedly effectively controlled.

Opposition Leader Jodi McKay was quick to capitalise on Ms Berejiklian's "personal nightmare", on Tuesday giving notice that she would move a motion of no confidence against the premier.

She accused the premier of being complicit in Mr Maguire's alleged corruption by neglecting her legal obligations to report it to ICAC.

But Ms Berejiklian says she didn't know details of Maguire's dealings, despite taped phone calls showing the pair had often discussed his business affairs.

Ms Berejiklian on Tuesday struggled to explain why the recordings played at ICAC didn't constitute knowledge of his business interests or prompt concerns of wrongdoing.

"Unfortunately you take people at face value and trust them," Ms Berejiklian told reporters.

"This person had been in parliament for 15 years and unfortunately, sometimes people are able to get away with things without a lot of people realising.

"At any stage, if myself or my colleagues ever had a hint that there was any wrongdoing done or any intent to do wrongdoing, of course that would have been reported.

"As I said yesterday, I trusted someone who didn't deserve to have my trust."

On Monday Ms Berejiklian denied she had deliberately blinded herself to information about Mr Maguire's finances in order to maintain plausible deniability.

On one occasion in September 2017 she told Mr Maguire she "didn't need to know about that" as he discussed a Badgerys Creek Airport deal which would help him to repay his debts.

Ms Berejiklian on Tuesday also declined to discuss the appropriateness of a sitting MP being involved in property deals, saying she didn't set the rules on the limits of MPs' business interests.

The motion of no confidence in the premier will be debated on Wednesday, keeping the awkward details of Ms Berejiklian's love life firmly in the spotlight.

However, it would need support from government MPs to pass.

With senior federal and state Liberal MPs on Tuesday rallying around Ms Berejiklian, that seems unlikely.

Prime Minister Scott Morrison on Tuesday nevertheless labelled Ms Berejiklian a "tremendous premier" who "showed a lot of courage" and had his full support.

"We are all human, particularly in those areas of our lives, and Gladys is an extremely private person and a person of momentous integrity," Mr Morrison told reporters.

Among her NSW colleagues, Energy and Environment Minister Matt Kean on Tuesday said Ms Berejiklian was "not the first person to suffer from a poor romantic choice" while Transport Minister Andrew Constance said the premier was "going nowhere".

Australian Associated Press