Experts say a rare species of albatross will be extinct by 2050 if the government and fishing industry don't do more to prevent bycatch.
It's estimated fishing kills almost 13,000 seabirds in New Zealand waters a year. Ocean advocates are calling on the government to impose the strictest controls on surface longline vessels to reduce deaths.
But the industry says the method is unproven in New Zealand waters.
Albatross are one of the most threatened seabird species on Earth. They're in global decline and longline fishing is significantly to blame.
"We've talked about the Antipodean albatross a lot, this is a species that will be extinct by 2050. This is an ecological crisis and the New Zealand government has not done enough and fisheries have not done enough to be able to stop that from happening," said Birdlife International's Stephanie Borrelle.
It's estimated surface longline fishing alone kills 300 to 500 albatross in New Zealand waters every year and it could be higher.
The government recently confirmed there were no observers on surface longliners in the fishery that includes Hauraki Gulf and Coromandel.
"We have some of our most threatened species - Antipodean albatross, Gibson's albatross, being caught on the east coast of the North Island and there haven't been observers on the boats there," Green MP Eugenie Sage said.
"Lack of observers means underreporting of seabird deaths."
Sage added that while work is underway to reduce seabird deaths from surface longlining, nothing has been done to address the significantly greater number of deaths by trawling.
"We are nowhere near achieving the vision in the national plan of action of zero bycatch of seabirds.
"Instead we have thousands of seabirds being killed every year by the commercial fishing industry."
Fisheries NZ says that's because observers were taken off some vessels for safety reasons.
"We're working closely with Maritime NZ to make sure that we are supporting them to deliver those rules around maritime safety because safety and health of our observers is of paramount concern for us," said Fisheries NZ director fisheries management Emma Taylor.
A recent review of commercial longliners' found they weren't adopting the voluntary measures to reduce seabird deaths so the government proposed changes.
Of the options being considered, a marine biologist says only one is an acceptable outcome.
"What we call three out of three so tory lines, bird scaring lines that hang off the back of the boat, line weighting to get the baits out of the reach of the albatross and petrels quickly because they are surface foragers and then setting at night when most birds aren't actually active," Borrelle said.
Currently fishers are only required to do two of those measures or use a device that shields their hooks until they reach a certain depth.
New Zealand advocates for other countries to use the best practice of all bycatch mitigation methods for surface longliners yet hasn't even enforced those for its own fishing industry.
However, in a statement to Newshub, Seafood NZ's Jeremy Helson said: "Without known success in New Zealand, the '3 of 3' model across all surface long line fisheries is unproven and therefore not a priority."
However: "We are open to research in this area and would support that."
"Fundamentally, fishers shouldn't be fishing if they are catching threatened species," Borrelle said.
New Zealand has a goal of zero bycatch of seabirds. Environmentalists say that's not realistic without wholesale change to how the fishing industry operates.