Gates remain open - not requiring payment for entry - at the city's rail stations as part of ongoing action by workers who want improved pay and conditions.
But there are no plans to repeat last week's service strikes, the Rail, Train and Bus Union says.
Those plans could change pending the outcome of a Fair Work Commission hearing on Tuesday when the union hopes to force the government to continue negotiating on conditions.
Mr Perrottet has threatened to take steps to terminate the enterprise agreement if industrial action continues.
He said it was "highly unusual" that at the same time, the federal Employment Minister Tony Burke had approached to the commission to flag the government intended to change the law to limit an employer's ability to scrap agreements.
"It demonstrates quite clearly the connection between Labor and the unions, focusing on themselves and not our state," he said.
"I'd say to the Labor party and Tony Burke; your focus should be on our people ... not standing up for the union bosses."
Unlike nurses, teachers and most other public servants in NSW, rail workers operate under federal employment law.
Mr Burke said his letter didn't mention the Sydney trains dispute and stemmed from the Albanese government's jobs summit.
Union NSW secretary Alex Claassens wasn't privy to the Mr Burke's letter but said it accorded with a seven-year campaign the union began when another train operator tore up an agreement during negotiations.
"I congratulate Tony for coming out and making that statement to say that that was an unintended consequence of the Fair Work Act," Mr Claassens said.
"It was never intended to be used in that particular format."
Meanwhile, industrial action on the city's metro construction will continue in the face of the premier's threats to scrap the enterprise agreement and an offer to modify "world class" intercity trains.
"We're trying not to inconvenience the public, we're trying really hard to inconvenience the senior bureaucrats and government ministers as much as we can," Mr Claassens said.
"The metro actions that are preventing some of the metro contracts from going ahead are not affecting the public."
The union says the intercity trains are unsafe, as the rail network's varying platforms and the widths of trains don't allow the fleet to operate without guards, as designed.
While pointing to the fleet being cleared by the safety regulator, the government has agreed to in-principle changes in an attempt to settle the enterprise bargaining rift.
The changes would move CCTV camera screens out of the driver's view, allow guards to monitor the screens and offer the guards space to step off the train to monitor platforms in person.
