Beach-goers are being urged to watch out for rips as a big swell hits the coastline.
Surf Life Saving New Zealand national lifesaving manager Allan Mundy said surf life-saving clubs were putting up signs warning beach-goers about the conditions.
"We're trying to make sure people stay out of the rips, which is difficult as we don't have patrols running at the moment."
He said a low sitting off the coast had brought heavy seas, which were expected to last for at least the next day or two before dropping off.
"Volunteers are finished for the season, so we ask the public to be vigilant and wise about where they are swimming.