A female orca has been hauled up in a fishing net near Akaroa.
A deepwater trawler pulled the orca up on December 6, about 30 nautical miles northeast of Banks Peninsula, the Ministry of Primary Industries says.
The Ministry had an observer on the vessel, who took photos and a tissue sample before the orca was returned to the sea.
The whale had suffered deep lacerations, but it is not clear what caused them.
Initial analysis suggests they were not likely to have been caused by propeller strikes or a fishing net, the MPI said.
"While the incident is very concerning, orca captures are not common," it said in a statement.
The only other time an orca has been recorded as being captured was in 1990.
Mammal experts are still working with the MPI and Department of Conservation to work out the cause of the orca's death.