Transport minister Jo Haylen resigns after taxpayer-funded car scandal

Ms Haylen said in a statement that she had let the public down and she was "very sorry for that".

She said her mistakes were now causing "my government damage".

"Politics is tough," she said. "Expectations are very high. I know that."

She reiterated that she had not broken the rules but acknowledged: "That's not the only test here".

Ms Haylen said from the moment she was appointed a Minister she had "worked my arse off".

"You don't switch on and off from being a Minister.

"You don't switch off being a Mum either.

"Combining the two can be difficult but I'm far from alone when it comes to that daily challenge."

Ms Haylen admitted on February 2 to using her driver for a boozy Australia Day long weekend lunch in the Hunter Valley, promising to pay back the $750 cost of the trip.

The trip on January 25 caused outrage after it was revealed a driver worked 13 hours, driving from his home in Rockdale, in southern Sydney, to Ms Haylen's Caves Beach holiday home in Lake Macquarie.

After picking up Ms Haylen, housing minister Rose Jackson, their husbands, and another couple he transported the group to Brokenwood Wines in Pokolbin.

He waited in the car for hours for the group to finish before dropping them back to Ms Haylen's holiday home and returning to Sydney.

On February 3, NSW Premier Chris Minns held a press conference and described the trip as a "massive error in judgement" but refused to sack Ms Haylen.

"The real error, in addition to NSW taxpayers being concerned about how their money is being used, is also the treatment of a public servant," he said.

Further allegations surfaced on February 3 that the Summer Hill MP asked her driver on multiple occasions to transport her and her son from her Caves Beach holiday house to her son's sporting games in Sydney.

Ms Haylen refused to answer questions by ACM on those allegations saying the guidelines "cover vehicle and driver use for public and private events".

NSW government ministers and the opposition leader are designated a ministerial vehicle and driver to help them with their role.

Mr Minns has now tightened the rules with drivers only to be used for official business purposes or private use "incidental" to official duties.

NSW opposition leader Mark Speakman said Mr Minns had "failed" a leadership test.

"For three days, Chris Minns had opportunity after opportunity to sack his Transport Minister," he said.

"The evidence was there and kept mounting. The repeated use of taxpayer-funded vehicles that no fair and reasonable person would accept was clear. But instead of acting, Chris Minns stalled, deflected, and hoped the problem would go away."