Five sea lions have died in one week after being caught by an Auckland Island squid fishery.
Fisheries New Zealand said their deaths unusual and incredibly disappointing.
Fisheries Management director Stuart Anderson said most squid fisheries use exclusion devices to help sea lions escape fishing nets if they are accidentally caught.
But he said not all sea lions escape in time.
Fisheries New Zealand will be consulting with the Auckland Island squid fishery responsible and updating their Operational Plan.
It comes after Fisheries New Zealand received reports of four Hector's dolphins killed in two separate incidents involving commercial fishers trawl fishing off the east coast of the South Island this summer.
Forest and Bird said commercial trawlers should not be fishing in the same patch of water an endangered animal lives and breeds in.