By Jack Gramenz in Sydney

Everyone but the rail union is fretting over the possibility Sydney’s New Year’s Eve fireworks might fizzle, but the impacts of industrial action and planned track work are already hitting festive season services.

Australia’s busiest urban rail network faces disarray on Saturday as shoppers attempt to pick up presents on the final weekend before Christmas.

Protected industrial action is limiting the ability to run trains and planned essential track work is pushing rail commuters on to buses when there is staff to drive them, Transport for NSW has warned.

The NSW government and rail operators are hoping the Fair Work Commission delivers a gift on Christmas Eve, when it hears applications to suspend the industrial action.

The Rail, Tram and Bus Union is confident the commission will take its side, dismissing the potential cancellation of fireworks as a tactic to bolster the government’s “quite weak” case.

“It’s not fair, it’s all done for an ulterior motive … and it should not be happening,” the union’s secretary Toby Warnes said on Friday.

The impact of New Year’s Eve industrial action would be negligible but it was up to rail operator Sydney Trains how many services were in action, he said.

“If the government sits down and negotiates an end to this dispute, there will be no interruption at all on New Year’s Eve,” Mr Warnes said.

Following the Federal Court ruling industrial action could resume on Thursday, Transport Minister Jo Haylen told reporters the union’s idea of negotiating was for the government to agree to its demands.

“We will not negotiate with a gun to our head … that’s why the government is taking legal action,” she said.

The uncertainty stemming from it all could be a killer for businesses, peak body Business Sydney director Paul Nicolaou said.

“Hopes of a bumper Christmas for the hospitality, entertainment and retail sectors have been shot to pieces and the potentially (sic) cancellation of the fireworks could force many businesses to the wall.”

Business NSW chief executive Daniel Hunter warned the cancellation of fireworks would be a disaster for businesses, workers, and the state’s international reputation.

“It would take us years to recover from this,” he said.

Both urged the union to compromise on its claim for four years of eight per cent pay rises.

But Mr Warnes denied responsibility for any cancellation, accusing the government of “hysteria”.

“It has resorted to scaring the people of NSW rather than resolving the dispute,” he told reporters.

It followed Police Commissioner Karen Webb warning she might recommend the fireworks be cancelled.

“I have grave concerns,” she told reporters on Friday.

Sydney Mayor Clover Moore said the city would do everything possible to ensure the fireworks could go ahead safely.