Rail chaos looms with 'whatever it takes' worker push

Commuters on the nation's busiest rail network could be hit with last-minute disruptions in the lead-up to Christmas after a court attempt to block industrial action was shut down.

The NSW government will still put forward an 11th-hour legal challenge to try to stop widespread cancellations on New Year's Eve as millions of revellers traverse Sydney.

Previously notified work bans by the Rail, Tram and Bus Union can resume after a Federal Court decision on Thursday.

One of the actions includes a network-wide shutdown unless trains run 24 hours across Thursday, Friday and Saturday nights.

"Members will do whatever it takes to achieve what they deserve," union secretary Toby Warnes insisted, adding it was up to the government to respond.

Transport Minister Jo Haylen could not say what that response would be or to what extent NSW's urban rail network would be disrupted.

"I expect that we will have a level of service available for passengers," she said.

"(Commuters) should check their travel apps and allow extra travel time at this stage."

The Federal Court's dismissal of the government's technical argument opened the door for 8000 workers to resume disruptive actions in the lead-up to Christmas.

Other action, spurred by the government's legal bid, could limit the number of trains that can run on New Year's Eve, with train crew planning to work progressively fewer kilometres each day from December 28.

The government would argue concerns for commuter safety and economic harm before the Fair Work Commission in a bid to cancel the action, Ms Haylen said.

Business groups have warned even the threat of work bans and strikes will change consumer behaviour and send struggling firms into bankruptcy.

The legal skirmishes are the latest escalation in a wages war stemming from April.

Rail workers continue to demand four annual wage increases of eight per cent, which Premier Chris Minns has said is unaffordable and could not occur while he is denying nurses a similarly costly claim.

The government previously offered 11 per cent across three years, including superannuation increases.

Nurses joined the rail union in solidarity on Thursday, urging the public to blame the government.

Mr Warnes said rail union executives would discuss withholding support from Labor on Friday, accusing the government of betrayal.

Opposition Leader Mark Speakman seemed to agree.

"Chris Minns created this mess," he said.

"He needs to work it out, sit down with these bastards and solve the problem.

"He now realises he can't afford to deliver the promises he made to his union bosses - that is why we are having this industrial chaos."