It's been called the "foot and mouth disease of the sea" and people on Aotea Great Barrier Island are getting sick of waiting for action to get rid of it.
The invasive seaweed caulerpa was discovered on the seafloors two years ago, however, the closure of many areas to fishing has produced some unexpected benefits.
For Great Barrier Islanders, the ocean and what lives in it are deeply entwined in their daily life, but now a scourge taints their shores.
When the tide recedes a thick green carpet of the seaweed is revealed.
"To put it simply it's just an absolute disaster, it takes over the seabed. It kills everything - there's just nothing left," kaumatua Sydney Davies said.
The foreign pest seaweed caulerpa washes up daily from where it has taken hold out across the sea floor.
How it arrived in New Zealand is still unknown. In one area authorities estimate it covers 80 hectares.
Caulerpa is well-established at Okupu Beach, there are swathes of it washed up at low tide and it's thick like a mat. You can see how this is smothering the sea floor.
Locals say efforts by authorities to slow the spread of caulerpa have been weak.
"I think we dropped the ball on this, we really did. Unprepared. And not really too sure what to do," Aotea Great Barrier Environmental Trust's Barry Scott said.
Scott said that failure to coordinate an action plan has resulted in the Ministry for Primary Industries (MPI) concluding caulerpa now cannot be eradicated.
"I think it kind of reflects [for] many Governments the focus is on agriculture, forestry, foot and mouth, those sorts of things and the ocean's forgotten. Totally forgotten," he said.
MPI is taking action to stop the spread, but allowances have been made to allow the community here to still fish - many rely on the ocean as the cost of living crisis bites.
Aotea Great Barrier Island is heading into summer with an anchoring ban extending along almost its entire western coastline out to 40 metres deep. Anchoring is permitted if a permit is obtained from MPI.
In this area highlighted in red, fishing that makes contact with the seafloor is banned, however line fishing, drift fishing, spearfishing and diving are permitted.
In the yellow area in Port Fitzroy, anchoring is permitted.
Caulerpa was first found on Aotea about two years ago. Since then it's spread far from the areas closed to boaties including the remote Oneura Bay.
For Hooked on Barrier skipper William Park, the fight against caulerpa is a juggling act.
"Obviously you want economic input to the island, you want biodiversity to remain the same. So I guess it's trying to strike a balance between the two," he told Newshub.
He said there have been some unintended benefits - in the areas where anchoring, fishing and diving have been restricted, sea life has thrived.
"We've had good snapper caught off Tryphena Wharf, good species off Okupu Wharf - sorry locals I'm giving away your spots - but it's really good to see," he said.
But the controlled areas are not a long term solution. Davies has a message to the new ministers - they need urgent funding and a national management plan.
"Get onto it. Hurry up. This has got to be one of the major, primary tasks that's gotta be done as a new Government," he said.
What's at stake was quantified in a study by the Institute of Economic Research - that valued the Hauraki Gulf at $100 billion.
"You've got a big fishing industry, you've got tourism, the natural environment, the biodiversity associated with that - the fish, mussels, scallops, natural seaweeds and the little critters in the seabed. The cost of not doing is catastrophic," Scott said.
An ocean-dependent community facing environmental disaster - urging the rest of New Zealand to take notice.
