Lifesavers could be forced to cut patrols and close beaches, unless they get more funding.
Surf Life Saving's Northern Region warns volunteers are being stretched to their absolute limit, as a result of the tourism boom.
More than 400 people were pulled from the sea last summer, twice as many as the five-year average.
Chief Executive Matt Williams said the service receives very little government funding, despite drownings being the country's fourth highest cause of accidental death.
"Our volunteer model which has worked for a hundred years will crack without the right support, without the central government there to prime the pump, and that's a real risk. Essentially our volunteers, we're putting our hands up and saying 'we need your help New Zealand if we are going to continue this service."
Williams said this year's season will be staffed at the current level.
But he said with an ever-expanding amount of people to look after and a constant need to upgrade their levels of service, the organisation needs to find a better way of meeting those challenges in the near future.
"New Zealand's number one form of free recreation is to go to the beach, and it's deeply upsetting I think for New Zealanders to think that the lifeguards wouldn't be there in the same fashion they have previously."
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