Nurses have voted to strike for an eight-hour period in a month's time over a breakdown in pay offer negotiations.

The New Zealand Nurses Organisation, which has 30,000 members working in district health boards, says members are angry at the first DHB pay offer last month and overwhelmingly voted to strike.

The union says the offer will have given most members a 1.38 per cent wage increase, below inflation.

However, the district health boards say reducing it to that is an oversimplification, and many nurses would receive much larger increases.

They say offered increases are between 1 and 11 per cent over the 27 month term of the agreement, and include a lump sump payment of $900.

NZNO spokesperson David Wait says the frustration from the low offer is coupled with the government's wage restraint announcement, which he said would effectively freeze most of their wages.

He says many nurses are on the top step of their pay scale, so have no room to move up.

The strike includes nurses involved in the vaccination rollout, but does not include nurses in managed isolation and quarantine.

The strike is from 11am to 7pm on Wednesday, June 9.

"Striking is always a last resort and we do have mediation with the DHBs scheduled for May 18-19 during which we will actively search for solutions that could avert strike action.

"The best alternative would be for the DHBs and government to be realistic and come up with an acceptable offer that would enhance the profession and recognise the contribution nurses have made before and since the pandemic," the statement reads.

Wait says further strike action is possible.

-RNZ.