Premier Dominic Perrottet says he should have been consulted before bureaucrats shut down NSW's passenger rail network, and that he is seeking advice on whether the decision broke the law.
After new Transport Minister David Elliott admitted he went to bed and let subordinates make the call on Sunday night, the Premier said he expected his cabinet to "be available around the clock".
But Mr Perrottet said he still backed the decision, made by Sydney Trains chief Matt Longland, which caused chaos for commuters in Sydney.
The state government maintains the network was closed for "safety reasons" ahead of planned low-level industrial action from the Rail, Tram and Bus Union (RTBU).
Mr Elliott told reporters yesterday he had gone to bed on Sunday night with an "inkling" there would be major disruptions but was not told of the decision to cancel all services.
Mr Elliott said even if he was called when the decision was reportedly made at 12:30am he "wouldn't have answered" because he was sleeping, and was "comfortable" in trusting transport bureaucrats to make the right judgement.
On Wednesday, Mr Perrottet said he was "incredibly disappointed" at the situation but still supported Mr Elliott as minister.
"My expectation is that ministers are available around the clock," he said.
"And I certainly am, and I expect the same of my ministers. I think he will reflect on that."
The Premier said he would have expected Mr Elliott to respect the decision to close the network had he been consulted, as he was satisfied there was "no alternative".
"If I had been advised, which I was not, I would have supported the position from Sydney Trains because my responsibility as Premier is to keep people safe and commuters safe on the train network," Mr Perrottet said.
He said he was working through whether bureaucrats broke the law in making the decision without first informing the minister: "That needs to be interpreted and I'm seeking advice".
"I should have been advised. I'm the Premier of this state and I didn't get a call, in whatever time in the morning, to let me know the train network's going down," he said.
"So I'm working through this, I'm not going to have a knee-jerk response ... to ensure this doesn't happen again.
"There's clearly been a breakdown in process."
It was revealed during Wednesday's press conference the Premier had still not seen the risk assessment report detailing why the network was closed.
Mr Perrottet said he'd had numerous briefings with transport officials since Monday morning and was satisfied the right decision was made.
He again blamed the RTBU for sparking the closure, claiming they on Sunday night "reneged" on a rostering agreement made with state officials the previous day.
The RTBU says it struck an agreement for protected action in the Fair Work Commission on Saturday before it resisted an attempt by the government to renegotiate in the commission on Sunday.
Train drivers showed up for work on Monday morning to find the network had been shuttered.
Limited services resumed yesterday and will continue for the remainder of the week.
Yesterday, Mr Elliott announced the government had been advised to withdraw its challenge to the RTBU's industrial action in the Fair Work Commission.