A 12-hour industrial action that would have resulted in some paramedics refusing all but the most serious calls has been ruled out of order amid a pay dispute.
Paramedics will face the sack by proceeding with a planned 12-hour industrial action, the industrial umpire has ruled.
Australian Paramedics Association NSW members had threatened to only attend emergency "lights and sirens" jobs from 7am on Friday as part of an ongoing pay dispute.
But the Industrial Relations Commission late on Thursday ruled the action by the smaller of the state's two paramedic unions would not be protected.
The action had been condemned as ridiculous and concerning by APA's rival, the Health Services Union (HSU).
The APA says it has 2500 members out of roughly 6000 paramedics statewide, while the HSU says it has 4100 paid members.
Regardless of their union, paramedics have taken escalating industrial action in recent months, fed up with their pay falling short of their skill level.
They were leaving NSW Ambulance in droves - either for other states or other industries, Greens health spokeswoman Amanda Cohn said.
"The Minns Labor government has managed to pay our teachers the best wage in the country and pay police trainees while they study," she said on Thursday.
"Where is the same support for paramedics?"
Two thousand HSU members, representing nearly half of all NSW Ambulance paramedics, have threatened to allow their professional registration to lapse on December 31 if their demands are not met.
HSU members want a pay increase of about 20 per cent to put them on par with Queensland, one of several states draining NSW of skilled paramedics.
Hours of negotiations between the HSU and the government continued this week.
Health Minister Ryan Park has acknowledged paramedics's pay no longer matches the skills required.
But he has cited incoming budgetary pressures, including a need to give 1100 nurses full-time contracts, for not kowtowing to union demands.
"We've had some very positive discussions over the last 24 hours," he said.
Opposition health spokesman Matt Kean said the government is putting patients across NSW at risk while the dispute drags on.
"The Minns Labor Government will be giving people a very unhappy Christmas and New Year by leaving NSW badly short of paramedics able to handle patients," he said.
"This is the result of Chris Minns' false election promises to give union bosses a pay rise without having to pay for it."