The whale was in good condition when it was found and measured about 3.6m long, she said.
DoC staff and iwi representatives from Rangitāne o Wairau went to the site and carried out the tikanga of taunaha on the whale.
Te Matahiapo Hynes provided karakia and cultural guidance on behalf of Rangitāne.
Given its rarity, DoC and iwi agreed to arrange a necropsy to try to determine the cause of death and learn more about the elusive species.
The whale was transported to the local DoC base and staff from Massey University’s Cetacean Pathology Unit flew down on Tuesday to carry out the necropsy and take tissue and organ samples for testing.
The necropsy was carried out under the guidance of tangata whenua, with appropriate tikanga observed throughout the process.
No obvious cause of death was found but the samples will undergo further assessment, and the whale was buried on Tuesday afternoon.