There is a $101 million shortfall in health funding in this year's budget, the nurses union says.
With the Council of Trade Unions on Saturday releasing an updated analysis of the government's 2017 budget unveiled in May, New Zealand Nurses Organisation chief executive Memo Musa said the shortfall was irresponsible.
"Health workforce training, contracted services, maternity services and public health service funding alone is short $36m," he said.
"Inadequate funding for preventive healthcare and community nursing results in more people going to the hospitals, which is not the way to keep New Zealanders well, or the best use of public funds."
Evidence of underfunding could already be seen in the fact preventable diseases were on the rise, Mr Musa said.
Funding shortfalls also heaped more pressure on already-stressed nursing staff, union president Grant Brookes said.
"This lack of investment in the workforce may really be the tipping point that triggers many in an aging nurse workforce to hang up their boots," he said.
The union said New Zealand needed to invest more into its health services so it could better prepare for multiple public health threats facing the country.
This included new threats associated with the increased movement of people, animals and food around the world, and the effects of climate change.