Washed up whale will be left to rot

Observers gather around the carcass of a sperm whale washed up aproximately 40km north of Muriwai Beach on the west coast of Auckland. Photo / NZPA

A whale that washed up last week around 40km north of Muriwai beach on Auckland's west coast will be left to rot, the Department of Conservation says.

The 11.5m long sperm whale was found late Friday night. DOC arrived the following day - Christmas - to take skin samples and advise iwi of the mammal's stranding in order to harvest the jaw bone, Auckland area duty officer Peter Smith said.

As the animal is not in an area visited often by people, the animal will be left to decompose, Mr Smith said, and will likely be covered by the sand over time.

He said there was a report of a second whale, but a search along the coast by Project Jonah found no other whales.

Mr Smith said it was likely the whale had died at sea and had washed ashore, as it was already decomposed when found.

It was not yet known what gender or how old the animal was, but Mr Smith said it was likely an adult.