Commuters have been caught in the crossfire as one of Australia's rockiest relationships was derailed again on Valentine's Day.
At least 70 per cent of train services were cancelled or delayed on Friday after more than 550 NSW train drivers and guards failed to arrive for work.
Train officials denied union claims workers had been locked out, begrudgingly urging commuters to avoid unnecessary travel or take taxis and buses to get to Valentine's dates and fulfil Saturday plans.
The latest breakdown in 10 months of rancorous wage negotiations between rail unions and the government came after management highlighted staff would be docked pay for participating in "go-slows" on Friday.
Unions also expressed fury over the government's refusal to repeat a $4500 sign-on bonus for every worker once negotiations ended.
Treasurer Daniel Mookhey described the resulting flood of absences as a "sneak strike" and denied accusations of a lockout.
"I have seen some of the communications from the unions ... the union is gaslighting Sydney," Mr Mookhey said.
"What they're saying to the public, to the government, to the courts, is clearly very different to what they're saying to their own members."
During an urgent hearing before the industrial umpire late on Friday, the union denied exerting control over the major spike in drivers calling in sick.
It also rejected efforts to voluntarily drop other industrial action despite lengthy talks in the halls of the Fair Work Commission.
"Having the industrial action there is a motivating factor" to progress bargaining, Rail Tram and Bus Union lawyer Peter Matthews told the commission.
Government efforts to halt the unprotected sick-leave action, expected to continue into Saturday, will be heard during a rare weekend hearing.
Further efforts to halt work bans will go before the commission's full bench on Wednesday.
Commuters were being held to ransom while the unions proved who ran the city, Opposition transport spokeswoman Natalie Ward said.
"On Valentine's Day, there are no flowers and chocolates for commuters when the Minns (government) is joined at the hip with the unions," she said.
"Neither of them wants an outcome here."
As of 1.30pm on Friday, more than 800 services had been cancelled and another 396 services delayed, Transport for NSW said.
The rail union's NSW secretary Toby Warnes said workers had not been directed to do anything and the union had simply advised its 7000 members of their rights.
Negotiations broke down over a $4500 payment included in the last agreement as a "one-off ... commencing on or after this agreement is made".
The government was only alerted to the clause when the union offered to forgo the payment for a slight wage increase, although state officials had not attempted to remove it during months of negotiations, Mr Warnes said.
But the treasurer said the clause was intended in lieu of previous back pay and the union had not previously demanded its retention.
Making such a payment would cost $60 million, Mr Mookhey said.
Union officials initially pushed for a 32 per cent pay rise across four years, but the government offered 15 per cent for the same period - including a federally mandated superannuation increase.
The union later provided a counter-offer of about 20 per cent across three years, which it rescinded after legal action was launched.
The rail network typically transports about a million people a day who have faced repeated disruptions as negotiations have dragged on.
