Green co-leader James Shaw has swapped his suit for a wetsuit, going scuba diving in Wellington to draw attention to the party's marine policies.
The Greens have announced a plan to set aside a third of New Zealand's oceans as marine sanctuaries - up from just 0.4 percent.
Shaw - who described himself as an infrequent diver - took a 20 minute dip in Taputeranga Marine Reserve off the coast of Island Bay on Sunday afternoon.
Kitted out in a full wetsuit, he told reporters he had dived in Thailand, Niue, Fiji, Egypt, and the Philippines, but "to my regret" never before in New Zealand.
The Green Party was turning its attention to the marine environment after championing freshwater issues for the past decade, Shaw said.
"We've made huge strides there. That work is only just beginning, but at least we've broken the back of it," Shaw said.
"[Our marine environment] is in dire straits and in real need of help... we are seeing a real collapse in our oceans and our fisheries."
New Zealand needed more "biodiversity hotspots" like Taputeranga Marine Reserve, Shaw said.
James Shaw in full diving gear. Photo: RNZ / Craig McCulloch
Following the dive, Shaw listed the array of sea life he had encountered, including an "enormous crayfish", blue cod, and some "quite territorial" blue moki.
"There's a lot of life out there - which 10 years ago there wasn't - and it just shows the importance that these marine reserves have."
Despite initially expressing trepidation at the crisp water temperature, Shaw assured sceptical reporters the water was "beautiful".
Currently 0.4 percent of the country's whole marine and coastal area is off limits to fishing and harvesting by international standards.
The Greens' plan would see a network of protected areas and sanctuaries created through new legislation.
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