No rules were broken in the use of a publicly funded car and driver by NSW Transport Minister Jo Haylen, but those regulations were likely to be changed following the "bad judgment", Premier Chris Minns said.
Ms Haylen and Labor frontbench colleague Rose Jackson were ferried by her ministerial driver from her holiday house south of Newcastle to lunch at a Hunter Valley winery on the Australia Day long weekend.
The private journey, which was allowed under current ministerial rules, took the driver on a 446km round trip from Sydney that lasted for 13 hours.
Mental Health Minister Rose Jackson has been criticised over transport choices to a long lunch. (Bianca De Marchi/AAP PHOTOS)
Mr Minns said he expected both ministers to learn from the error of judgment, but they would retain their roles.
"I'm not going to sack the ministers," he told reporters on Monday as he faced a barrage of questions over the trip.
"Both of them are in big portfolios ... we need continuity in those jobs," Mr Minns added.
Ms Haylen has been battling a long-running industrial dispute with railway workers that has repeatedly threatened to shut down the state's train network, while Ms Jackson, as mental health minister, is dealing with a staffing crisis as public psychiatrists resign en masse.
The transport minister has promised to pay back the $750 cost of the trip and acknowledged it did not pass the "pub test".
Mr Minns said the journey complied with the current rules but that did not make it acceptable.
"It's bad judgment by any stretch of the imagination," he said.
"The best thing I can do is look at changing the rules to ensure that this isn't done again."
Opposition Leader Mark Speakman said the premier's response to the revelations should serve as a test.
"Unless he sacks these ministers, it's a failure of leadership and integrity on the part of Chris Minns," he said.
Mr Speakman is also entitled to a taxpayer-funded driver, but he said that privilege came with the responsibility to use it appropriately without incurring additional costs to the taxpayer.
He acknowledged he had a driver take him home from a "work-related" Liberal party function and also sent them on errands during shifts.
"If they're otherwise sitting there and they've got nothing to do, and it's not costing the taxpayer anything, then I've asked them to pick up my dry-cleaning ... clothes that I do wear to work," Mr Speakman said.
"It's clearly different from spending the amount of money that was spent here, sending a van and a driver up to the Hunter Valley for a boozy lunch."
Ms Haylen has previously come under fire for hiring ex-Labor staffer Josh Murray to lead the transport department and the apparent use of a public servant in her office for political work.
