The Green Party is concerned changes to how researchers determine the cause of death of seabirds could threaten many already close to extinction.
The Department of Conservation may soon request photos of seabirds killed by commercial fishermen be sent to New Zealand, rather than the bodies.
Until now, scientists have carried out autopsies on birds such as albatross and petrels to determine how fishing may be harming them.
DoC spokesperson Nick Hirst says government observers are on almost all fishing boats now, meaning an increase in dead birds collected.
Mr Hirst says the department can't afford to send all back for post-mortems. Some of the four most commonly caught birds will be returned, but many will be analysed by photograph.
The Green Party's oceans spokesperson, Gareth Hughes, says analysing photographs is not as reliable as post-mortems and more needs to be done to save endangered seabirds.
DoC says the information will be linked to databases at the Ministry for Primary Industries.