Transport Minister David Elliott has told NSW rail unions he cannot save them as Premier Dominic Perrottet threatens to go to the Fair Work Commission if workers strike again.
Most timetables on Wednesday were reduced to 30-minute frequencies, with services suspended on the T5 Cumberland and T7 Olympic Park lines.
Commuters were frustrated as rail workers refused to operate foreign-made locomotives comprising about 70 per cent of Sydney Trains' fleet.
Compounding disruptions, bus drivers are striking in Sydney's inner west in a separate dispute with one of the private companies contracted to run buses.
Region 6, including the inner west, some of the CBD, Olympic Park, Strathfield and Rockdale will be affected by six hours of stop work action split across Wednesday.
Wednesday's refusal to drive foreign trains is the culmination of a month of industrial action.
Unions want a new enterprise agreement and modifications to the Korean-built intercity trains, which it argues are not safe to operate in NSW.
Mr Perrottet said the government has made its "final offer" to modify the New Intercity Fleet (NIF).
"Negotiations are over," he told reporters on Wednesday.
Any further industrial action would lead to the current enterprise agreement's termination and the Fair Work Commission being asked to settle the dispute, Mr Perrottet said.
"It's very clear in my view, the union is using our people as political pawns. It ends today," the premier said.
The Rail, Tram and Bus Union (RTBU) has been negotiating with three different ministers and has called on the premier to take over and meet directly several times throughout its industrial action, which continued throughout August.
Mr Elliott delivered the premier's message during a meeting with the unions on Wednesday and was at parliament house about an hour later.
He told reporters beforehand it would be a very short meeting.
"I'll be walking in telling them that I have now lost all negotiation powers, the premier has instructed me to give them the enterprise agreement.
"We will be putting that agreement to the vote, if the vote is no, the agreement gets shredded," he said.
"That includes the NIF," Mr Perrottet interjected.
"That includes the NIF," Mr Elliott repeated.
"They are losing everything, and of course if there is a shredded enterprise agreement that means we start all over again, and good luck," Mr Elliott said.
Hearing those comments minutes before the scheduled meeting, RTBU NSW secretary Alex Claassens said he was speechless.
"I'll listen to what David Elliott's got to say personally from his mouth and if he tells me he's lost negotiating power, then we're in trouble," he said.
Mr Elliott said he had tried to help the union resolve its dispute, even fighting with other ministers about it.
"They have moved the goalposts just once too many times, so I couldn't save them," he said.
Opposition Leader Chris Minns also called for a resolution.
"The message from the NSW parliamentary Labor Party couldn't be clearer: we don't want the strikes," Mr Minns said on Wednesday.
Mr Claassens said the union was disappointed.
"They are on a unity ticket with the Liberal Party and that is no good for the workers of NSW," Mr Claassens said.
"We will go back and have conversations about what it means to be in the Labor Party."
