A $264 million olive branch has been extended to rail workers to ease train safety concerns and avert more disruption, but their union says it has been "burnt too many times" to take the verbal deal.
The Rail, Tram and Bus Union has been locked in long-running negotiations with the government over safety modifications it wants on the $2.8 billion Korean-made intercity fleet.
Train drivers have been taking industrial action for months to pressure the government, which finally relented on Wednesday, agreeing to spend $264 million to upgrade the mothballed fleet.
Transport Minister David Elliott said a verbal agreement had been reached and he expected the union to end this week's industrial action.
"We have agreed to their (union) request for one agreement and all the original discussions and negotiations with regards to their allowances and pay have also been agreed to", he told reporters on Wednesday.
"The NSW government expects the union to terminate industrial action straightaway in the best interests of the commuters."
He said the settlement was reached so the train system can run smoothly once again without disruptions, noting "it's a small price to pay".
"The cost of modifying these perfectly good trains is a lot less than actually disrupting our economy and not having these trains running," Mr Elliott said.
However, the RTBU said on Wednesday it needs the guarantees in writing and would push on with its industrial action.
"Rail workers and commuters have been burnt too many times to believe what one minister in one meeting says," said the union's Secretary Alex Claassens.
"We need to see the whole package in writing to make sure this isn't just another case of the NSW government playing political games."
Transport for NSW warned the union ban on driving foreign-owned trains on Friday would have a knock-on effect on Sydney services, with a reduction of 70 per cent during peak periods leading to delays and cancellations.
Dominic Perrottet's government has also been battling industrial action launched by the teachers union.
A historic 24-strike on Thursday by NSW public and Catholic teachers is the result of the state government's failure to address chronic teacher shortages, unions say.
The action by 85,000 public and Catholic school teachers will be the third strike in six months and is expected to affect about a million families, just a day before two weeks of holidays.
Thousands of teachers are expected to descend on Sydney's CBD after the NSW budget offered no more than a 3.5 per cent pay rise.
It's the first time in more than 25 years the NSW Teachers Federation and Independent Education Union NSW/ACT have joined forces to strike for 24 hours.
"We have a crisis in the form of a teacher shortage, a crisis that is the government's own making," Federation President Angelo Gavrielatos told reporters on Wednesday.
"The government has known for years the causes of this crisis: uncompetitive salaries and unsustainable workloads.
"Students have been denied not only their learning opportunities but are also being denied their futures."
Mr Gavrielatos urged the government to retain teachers in the stretched sector by lifting wages by around seven per cent in order to keep up with inflation and living costs which have spiked in recent months.
"Teacher salaries have declined relative to other professions over the last 30 years ... our claim is clear based on an independent inquiry... recommending a five to 7.5 per cent increase per annum," he said.
Australian Associated Press
Sign up for our newsletter to stay up to date.