The clock is ticking down on a rapidly deteriorating shipwreck, which iwi and researchers are warning could release up to 1400 tonnes of oil into the Hauraki Gulf.
The passenger liner RMS Niagara has been laying on the seafloor, 40 kilometres southeast of Whangārei, for more than 80 years now.
It was full of fuel oil when it was hit by a German mine and now lies 120 metres deep.
Local iwi Ngāti Manuhiri regularly patrol the Hauraki Gulf on their repurposed former police boats.
Using underwater cameras, the iwi monitors the health of the seabed, and kaimoana such as tipa (shellfish), kuku (mussels) and tamure (snapper).
Chief executive of the Ngāti Manuhiri Settlement Trust Nicola Macdonald said "every type of kai that you can think of, we have it here".
"If the Niagara was to breach its hulls, they will be wiped out. Nothing can survive. No biodiversity will survive ingesting crude oil."
Shipwreck researcher Keith Gordon has visited the wreckage frequently in the past three decades.
"The wreck is collapsing at quite a fast rate," he said. "A lot of features that used to be there, are now gone or have just collapsed."
On a recent visit to the site, Gordon said there was an "area of a bright sheen".
"You could smell it... the strong pungent smell."
On previous visits to the site, Gordon had observed "oil slicks from the wreck up to 14km long".
His fear is that nearby marine reserves, Poor Knights and Goat Island, would be destroyed in the event of a large spill.
Macdonald said a major leak from the Niagara would "be worse than the Rena", referring to the devastation caused to the marine environment and shoreline when a container ship ran aground in Tauranga in 2011.
"We're looking at something like what happened in the Gulf of Mexico. Our entire ecosystem will be wiped out before our very eyes," she said.
The Rena leaked 350 tonnes, whereas Gordon estimates there could be 1400 tonnes of oil in the Niagara.
"If the ship suddenly did do a big breach and a lot of oil, we don't really have the facilities here to do a clean up of that volume of oil," Gordon said.
"They would have to get the equipment from Australia probably to come across - and that's going to take time. In the meantime, if there's a lot of oil floating around out there and coming onshore, it would do a lot of damage."
The problem is - no one knows for sure how much oil is still left onboard, as there have only been visual surveys of the wreckage.
"We do need to get Maritime New Zealand under the water and doing the survey for us, so we know exactly what we're dealing with," Macdonald said.
Maritime New Zealand has known about the risk of an oil spill for decades, and said in 2000 "if a major structural change occurred... the oil could easily come to the surface 'en masse'".
However, it also said it was "unlikely that the bulk of the remaining oil would be released at one time" and that the "more likely scenario" is "occasional reports of small amounts of oil".
Gordon said it wasn't a matter of "if it happens" but "when". He is just one party who has reported concerns to Maritime NZ.
In 2019 and again in 2020, Maritime NZ requested funding from the Government for further investigation of the wreck - to drill into the remaining bunkers to find out how much oil is still in there.
Both requests were declined.
"It's far cheaper to get that oil out now than the cost of cleaning it up later, either way it's going to cost money," Gordon said.
"The major thing first is to get an assessment survey done."
In a statement, Associate Minister for Transport Matt Doocey told The Hui the Government has no plans to commission any further survey work.
He said it would rely on the partial visual surveys carried out by the Royal NZ Navy in 2021 and 2022.
Meanwhile, a spokesperson for Maritime NZ said a team were set to visit the site in February this year, but couldn't due to "operational and technical challenges".
The government agency is not regularly monitoring the situation, the spokesperson said, as they are not funded to do so.
Maritime NZ said that natural processes would break down the small amounts of oil that have been reported.
The spokesperson added "there is no information to suggest shorelines or flora and fauna have been affected".
Made with support from Te Mangai Pāho and New Zealand On Air.