Illegal fishing may have resulted in the death of two endangered Hector''s dolphins found entangled in a net on a beach north of Christchurch.
The dolphins were found by a member of the public washed up near the Waimakariri River mouth on Wednesday, within the limits of the Banks Peninsula Marine Mammal Sanctuary.
A Ministry of Agriculture and Forestry investigation is under way.
Conservation Minister Kate Wilkinson says the deaths should never have happened.
"These dolphins were found on the beach well inside the sanctuary, which means there is a distinct possibility this was the result of illegal fishing activity," she said.
Set net fishing is banned out to four nautical miles along most of the east coast of the South Island.
Green Party oceans spokesman Gareth Hughes wants the set net ban better monitored by the government, by increasing aerial monitoring of the area and having more observers on commercial fishing boats.
"The set net ban doesn't protect dolphins if the ban is not enforced," he said.
Mr Hughes is also calling on the government to extend the set net ban further offshore.
Managing director of local tourism company Black Cat Cruises, Paul Bingham, says current measures to protect Hectors dolphins aren't good enough.
"Two Hectors dolphin deaths are significant for a population of only 900 around Banks Peninsula," he said.
"These dolphins live close inshore and are particularly at risk of getting caught in set nets and drowning."
There are about 7000 Hector's dolphins left, making it one of the world's most endangered species of dolphin.
NZN