Earlier this year, Auckland councillors voted to oppose oil exploration in a sanctuary home to the dolphin, but stopped short of following Christchurch City Council and opposing any exploration, while a survey suggested Kiwis would be happy to pay for
greater protection for the dolphins.
Population numbers - which environmentalists have generally put at 55 and the Department of Conservation has estimated at between 48 and 69 - had dropped 97 per cent as a result of fishing since the 1970s, NABU International Nature Conservation Foundation said in a statement.
The group stated the numbers had dropped from 111 in 2004 to 59 in 2010/11, and claimed the absence of man-made deaths, such as dying in fishing nets, would set the dolphins back on the road to recovery and allow numbers to grow to 500 individuals in 87 years.
Because Maui's dolphins could only cope with one human-induced death every 10-20 years, immediate conservation measures are urgently required, NABU said.
There has been debate around figures surrounding the dolphin's population and its extinction deadline.
Last year, a Ministry for Primary Industries spokesperson told the Herald that while there was no debate numbers were at a "very low level", the Government had not seen any analysis or evidence that supported research suggesting existing protection measures would lead to the Maui dolphin's functinal extinction within the next two decades.
Dr Maas said the new figures were an "unmistakable wake-up call", arguing New Zealand had to stop placing the interests of the fishing industry above biodiversity conservation.
Presently, the Government has in place a range of set net, trawling and drift net restrictions throughout the dolphins' habitat, while there are also restrictions on seabed mining and acoustic seismic survey work within the boundaries of the West Coast North Island Marine Mammal Sanctuary, which was extended in 2013 to include more of the Maui dolphin's range in the Taranaki area.
The Government was also reviewing a threat management plan already in place for the dolphins, with the programme to be informed by a marine research and advisory group of scientific and stakeholder experts.
University of Auckland scientists have just completed the first year of a two-year field estimate, but did not yet have figures updating the last estimate in 2010 of 55 mammals over one year of age.
In an interview with Radio New Zealand, university marine biologist Rochelle Constantine noted the NABU numbers were based on a model.
The seafood industry has disputed Dr Maas' figures, calling them "exaggerations".
Seafood New Zealand chair George Clement said current fishing restrictions were working, with no captures of dolphins in more than 900 days.
Mr Clement claimed the main threat to the dolphins was not from fishing, but the disease toxoplasmosis.
Meanwhile, a crowd-funding campaign by a Wellington game developer Gamestarter has raised $6560 of the $10,000 it is aiming for to create a mobile game around the plight of the dolphins.
The mobile game lets players try to break the world freediving record as champion free-diver William Trubridge, while saving Maui's dolphins from gillnets.
Their crowdfunding campaign on PledgeMe is looking to raise $10,000 for the development of the game, which they hope will help spread the cause throughout all of New Zealand and the world.
