Hundreds of paramedics have reported they are looking to leave NSW for more lucrative work in other states as a long-running stand-off over pay heads to the industrial umpire.

The bitter dispute has plagued the Minns government for more than eight months as paramedics point to higher salaries offered to their colleagues in the ACT, Queensland and Victoria.

The Health Services Union (HSU) and government officials will meet at a hearing before the state's Industrial Relations Commission on Monday afternoon.

The union rejected a pay offer last week that would have lifted salaries by an average of 19 per cent over four years.

The complex offer did not match base pay for Queensland paramedics and would leave NSW workers short-changed, the HSU said.

The union is instead pushing for a 20 per cent increase in paramedics' base pay, which officials say is warranted to reflect rising workers skills and responsibilities.

If a deal is not struck by the end of the year, 2100 paramedics have threatened to allow their professional registrations to lapse on January 1.

This means paramedics would be legally unable to attend triple zero calls from New Year's Day if they do not apply for renewal.

Health Minister Ryan Park warned the state's triple zero emergency system could collapse on one of the busiest nights of the year if the matter was not resolved and the government was willing to keep refining its offer.

"But we always have to understand that we are working, just like any government and just like any family is, in a budgetary challenging position," he said.

The HSU has accused the government of sharing misleading figures as part of its proposed pay rise, including claims that experienced paramedics were being offered a deal that would result in them getting more than $166,000 a year.

NSW secretary Gerard Hayes the union was looking for an increase to paramedics' base pay that reflected the value of their work, not unrealistic projections based on overtime.

"We can't fill rosters now because we can't attract and we can't retain, because we are so far behind," he told ABC radio.

A union survey indicated hundreds of NSW paramedics were actively looking for work in other states, while training courses were running at a fraction of their usual intakes, he said.

Premier Chris Minns said the government offered to import the Queensland pay system into NSW, but the union rejected that option as it would result in worse overtime rates and conditions, despite higher base pay.

But Mr Hayes said NSW paramedics were yet to be offered the same base pay rate as their Queensland counterparts and it should not be a "big deal" for them to get a 20 per cent increase in their standard salaries.