Mr Maguire gave evidence at a private session of the Independent Commission Against Corruption (ICAC) on Thursday about matters of "considerable personal privacy" between Ms Berejiklian and himself.

Part of that evidence was later released publicly, including questions about when the relationship started.

"I don't know that I could put a date on it. We were always good friends and slowly over time the relationship developed. I couldn't tell you when it started," Mr Maguire said.

"At least from your perspective, were you in a close, personal relationship with Ms Berejiklian at some time in calendar year 2014?"

Counsel assisting ICAC Scott Robertson asked, "Yes," Mr Maguire said.

In 2014, Mr Maguire was Parliamentary Secretary to the Premier for Rural and Regional Affairs and Ms Berejiklian was Minister for Transport.

Ms Berejiklian told ICAC last week that she started a relationship with Mr Maguire in 2015 and ended it in August this year.

Ms Berejiklian has now told the Sunday Telegraph that at one point she had wanted to marry Mr Maguire but would never speak to him again after ICAC.

"I can formally say to people I've given up on love," Ms Berejiklian told the Telegraph.

"I'm just going to say I have always put my job first, rightly or wrongly, and that will now continue indefinitely."

Ms Berejiklian maintained her position that she had done nothing wrong in her relationship with Mr Maguire or in handling what she knew about his business affairs.

Federal Labor opposition spokesperson for education, Tanya Plibersek, told the Insiders TV program on Sunday that ICAC was "quite properly looking at whether the Premier turned a blind eye to [Mr Maguire's] behaviour".

"I feel, actually as a human being, very personally sorry for the Premier," she said.

"It is hard to form and maintain relationships in our line of work, but there is never any excuse for corrupt behaviour or turning a blind eye to corrupt behaviour."