Rallies will be held across the state to protest changes to workplace compensation.

Nurses have voted to stop work over the NSW government's push to overhaul the compensation scheme for injured workers.

NSW Nurses' Association general-secretary Brett Holmes said rallies would be held across the state tomorrow, when changes to WorkCover are handed down in a report to parliament.

He said a preliminary assessment of the plan indicated that nurses and midwives could face a 20 per cent pay cut in the fourth month after their work injury.

"Hundreds of nurses and midwives, in public and private hospitals and aged care facilities, suffer serious injuries each year," he said.

"These are not always high profile injuries, but the 'sprain and strain' injuries nurses and midwives often suffer can cost them thousands in lost income under the current system.

"The O'Farrell government plan will make those losses even worse."

Holmes said nurses were also opposed to plans to abolish journey claims for shift workers and its plan to stop all compensation payments after 130 weeks.

"This attack on the financial security of injured NSW workers, in both the private and public sectors, comes on the back of its attack on the industrial rights of public hospital nurses and midwives," he said.

The NSW government claims premiums will skyrocket if a $4.1 billion deficit isn't reined in, while unions fear the WorkCover reforms will lead to injured workers having their benefits slashed.

Elsewhere, the NSW state government announced in today’s budget funding for NSW public hospitals to employ an additional 540 nurses. While the union welcomed the commitment, it says the extra positions have been in the pipeline for more than a year.

"This is consistent with the numbers that were negotiated with the previous government and committed to by the current government," said Holmes.

Holmes said a promise to hire some 40 new clinical nurse educators was new.

AAP.