Conservationists and marine law academics are calling for reforms to the Fisheries Act to further protect endangered species from falling victim to bycatch.
Ministry of Fisheries figures show more than 3000 seabirds die each year, and NIWA says up to 150 dolphins are killed.
A symposium held in Wellington on Thursday discussed ways of strengthening powers within the Act.
University of Otago senior law lecturer Nicola Wheen says the wording of the Fisheries Act is not strong enough to seriously deal with issues such as unintentional catches by commercial fishing operations.
She says the current legislation predominantly uses the word 'may' when authorising ministers to act to protect marine animals, and should be amended to 'must'.