NSW Transport Minister David Elliott says he can't rule out a repeat of the total shutdown of the train network on Monday if the rail union goes ahead with threatened industrial action.
He has also offered to give commuters free travel every Friday for a year if the union promises not to strike during that time.
Mr Elliott doubled down on comments made during the February shutdown, once again accusing the union movement of "industrial bastardry".
"People are desperate to get back to work on the back of a pandemic and the natural disaster and the union movement today wants to play games that will bring this city to a standstill," he said.
The NSW Rail, Tram and Bus Union (RTBU) earlier said it would use industrial action to "force" the state government to offer free fares to commuters every Friday until June.
RTBU secretary Alex Claassens said the move was fallout from the government's decision to shut down the train network without warning last month, locking out workers and leaving thousands of commuters stranded.
"We're now calling on the government to give everybody a fare-free day every Friday until June," he said.
"And if they don't do that, we're going to take industrial action that will force them to."
The Transport Minister said he was prepared to "up the ante", offering the union a deal.
"If you promise not to strike for a year, I'll give fare-free Fridays for a year," he said.
Mr Elliott warned there was a "strong possibility" that separate industrial action planned for Monday would spark another network-wide shutdown on Sydney trains.
"The advice I have got is that there is every possibility we won't be able to run the network," he said.
The union confirmed that the industrial action planned would be similar to that taken in the lead-up to February 21, when Transport NSW took the eleventh-hour decision to shut down the entire network due to "safety concerns".
The union defended its campaign for free fares for passengers on Fridays, saying the Premier needed to "own up" to disrespecting commuters.
"We're going to put on a range of measures and as soon as the government announces a fare-free day on Friday we're going to withdraw that."
He said the move would breathe new life into Sydney's struggling CBD and the union understood the government was "going to suggest it anyway".
Mr Elliott confirmed he was considering ways of compensating train travellers for last month's disruption.
"We want to make sure whatever cost to the taxpayer gives the maximum bang for buck in terms of economic activity," he said.
Commuters yesterday experienced significant delays on the network, which has been recently plagued by problems caused by last week's torrential rain.
Sydney Trains has warned passengers to be prepared for disruption on the train network over the next two weeks.
"Sydney Trains is focused on supporting customers who are returning to work after COVID impacts and [as] NSW recovers from the devastating floods," a spokesperson said.
"The prolonged period of industrial action is making that difficult."
The RTBU and the state government are locked in ongoing negotiations for a new enterprise agreement to replace the old one which expired last May.
The parties are due to meet for negotiations on Thursday.
Mr Elliott said he would not be present at the meeting as he would be in Lismore, meeting homeless veterans.
Sydney Trains said it was committed to working with the unions to reach an agreement.
Mr Claassens said the renewed industrial action had been partly fuelled by a stalling of negotiations in recent weeks.
He also said despite issuing a court subpoena, the union still had not seen the risk assessment report the government said justified a late-night call to close down Sydney's rail network last month.
At the time, Transport for NSW secretary Rob Sharp said it had no option due to industrial action.
"This was a difficult decision to make but we cannot, and will not, compromise on safety," he said.
NSW Premier Dominic Perrottet claimed the RTBU had conspired to cause "mass disruption" to the state.
Mr Elliott later faced questioning over when he knew about the shutdown, and claimed to have been sleeping when the decision was made late on Sunday, February 20.
On February 24, the ABC revealed senior transport bureaucrats were discussing a potential two-week shutdown days before the call was made.
