Rest homes say they are losing nurses to public hospitals at an alarming rate.
They are blaming higher wages being offered to hospital nurses, and say changes to immigration requirements are needed.
The Aged Care Association said a survey showed there were 500 nurse vacancies in rest homes - 10 percent of all registered nursing positions in the sector nationwide.
Chief executive Simon Wallace said nurses had always moved between the sectors but it was far more pronounced now, driven by pay rises being offered by district health boards in ongoing pay talks.
He said it was driving pressures in rest homes that received a 2 percent DHB funding boost this year.
"Nurses are under a lot of pressure, I mean we're dealing with an increasing number of residents in aged care now with the ageing demographic.
"The residents are coming in with a lot more acuities than they've ever had, so everyone's under pressure and that's certainly reached a high point at the moment."
Mr Wallace said the government's promise to provide 500 extra hospital nurses would double current rest home vacancies and might lead to bed closures.
As well, he said immigration changes in 2016 meant nurses were moved from a long-term skills shortage list to an immediate skills shortage list, increasing uncertainty for nurses coming here from overseas.
"We have the potential to be 1000 nurses short in our sector over the next six to 12 months, unless we can get some relaxation, particularly on those immigration policies."
He urged the government to reverse the 2016 immigration decision that removed aged care nurses from a long-term skills shortage list.