NSW’s premier remains willing to modify mothballed “world-class and safe” trains to appease rail workers, despite threatening to trash such an agreement if Sydney’s rail strikes continue.

Ticket gates remained open at train stations over the weekend, past the government’s deadline for the Rail, Tram and Bus Union to abandon all industrial action by 5pm on Friday.

Continued action was to result in the tearing up an agreement to alter a fleet of warehoused Korean-built intercity trains the unions says are not safe to operate in NSW but the premier considers “world-class”.

Dominic Perrottet denied the open Opal gates were part of his threat.

“That clearly doesn’t inconvenience commuters,” the premier told reporters on Monday.

“I’ve made this incredibly clear.

“Let me say this for the last time; if there is any action on Sydney trains that impacts people’s ability to get to work, home, school or their medical appointments  … we will seek to terminate.”

The dispute will head to the Fair Work Commission on Tuesday in the union’s bid to force the government to continue negotiating.

Transport Minister David Elliott and Industrial Minister Damien Tudehope say the unions’ application is a delaying tactic to drag out negotiations and continue a political campaign of disruptive strikes.

The application came a day before federal Employment Minister Tony Burke wrote to the commission about an intention to change enterprise bargaining laws sometime in the future.

While Mr Burke says the letter didn’t mention the Sydney trains dispute and stemmed from the Albanese government’s jobs summit, the NSW ministers blasted it as an intervention.

Mr Perrottet found Mr Burke’s letter “highly unusual” given it was written amid “significant action” by the union “against the people of our state”.

“It demonstrates quite clearly the connection between Labor and the unions, focusing on themselves and not our state,” he said.

While strikes like those that plagued the network last month are off the table, the RTBU says it won’t abandon its remaining industrial campaign, which includes leaving station gates open and banning fines from being issued, in the coming days.

“Our members are resolute, our delegates are resolute, we will not be blackmailed,” he told reporters on Friday.

The union says the fight over the intercity fleet is about safety, and while the trains were designed to operate without guards, the NSW rail network’s varying platforms and the widths of trains don’t allow it.

Modifications would move CCTV camera screens out of the driver’s view and allow guards to monitor them, as well as step off the train to monitor platforms in person.

– AAP