Earlier this month, the Nurses Organisation union (NZNO) agreed to consider the government's pay offer, but it was rejected in a ballott which closed early this evening.
The NZNO lifted a notice for a 24-hour strike on 29-30 July so members could consider and vote on an amended offer, but strikes planned for 19 August and 9-10 September will go ahead "unless an acceptable offer is made".
NZNO lead advocate David Wait said that while the DHBs had made promising moves on pay, the offer contained "too many ambiguities".
"Members have been clear from the beginning that their safety at work and the safety of their patients is a priority, and that is where they most deserve certainty.
"Better pay will make nursing more attractive, but it is not clear how the DHBs will be held accountable if they do not provide safe staffing. Nurses don't want more vague promises that the problem will be fixed in the future - which is what we have received once again."
Nurses were standing up for the future of their profession and wellbeing of New Zealanders, Wait said.
"This won't happen until the DHBs put accountability systems in place so nurses know things really will change and that their employers will listen when they feel unsafe at work."
The NZNO would continue with negotiation, bargaining and mediation with district health boards (DHBs), Wait said.
"We want the DHBs to come back with an offer that provides certainty over how safe staffing will be addressed. Members are tired of ambiguity."
Whether or not the strikes would go ahead depended on negotiations, Wait said.