A review of the effectiveness of area-based management to reduce dolphin bycatch found that if protection was extended out to 100m deep throughout the Hector's habitat, it could recover significantly, Associate Prof Liz Slooten says.
She is hoping this information will help push the Government to increase protection measures during its forthcoming review of Hector's risk management.
A long-term study of the Banks Peninsula population showed that where gill nets and trawling were banned, numbers had increased 5.4% compared with previous decreases of 6% a year, the review, published in international journal Endangered Species Research, said.
The population was stable or still declining at less than 1%, which was substantially slower than in the past, she said.
Most dolphins did not range beyond waters of 100m deep and if 100m was adopted, their population could recover to about 15,000 in 40 years, she estimated.
''If they extend it out to 100m, it'll definitely solve the whole problem.''
It was an approach that had been officially backed internationally by marine mammal scientists, including the International Whaling Committee scientific committee and the International Union for Conservation of Nature (IUCN), although New Zealand did not vote for it, she said.
The review would be submitted as part of the forthcoming Government review of the dolphin's threat management.
However, although in the past the science had been clear for increased protection, it had not translated into management measures, she said.
''We'll be keeping a close eye on it.''
It was hoped the launch of her and fellow marine scientist Prof Steve Dawson's new book Dolphins Downunder - Understanding the New Zealand Dolphin last night would help the public's awareness of the problems facing the dolphins, she said.
There were estimated to be 7270 South Island Hector's dolphins and as few as 55 North Island Hector's dolphins, known as Maui dolphins.
