Police have released a photograph of a man allegedly seen hacking off the valuable jaw bone of a dead whale on Pāpāmoa Beach.
The incident happened on February 15 near the Kaituna River.
The man was described as being 30-40 years old with tattoos on his upper left leg, face and neck.
He was driving a Blue Toyota Hilux ute with the front registration plate taped over.
The police say it was an offence under the Marine Mammals Protection Act to take the bone.
They urged anyone who recognised the man or his truck or anyone who witnessed this incident to contact Papamoa Police on 07 572 2440 or to call Crimestoppers anonymously on 0800 555 111.
The whale, thought to be a sperm whale, was found washed up and decomposing on the beach.
Members of the public were guarding the whale and authorities were in the process of arranging formal security when what witnesses described as two men in a ute turned up and hacked the jaw off with chainsaws.
The Department of Conservation, local iwi and a carver condemned the brutal and unceremonious removal of the jaw, considered the most spiritually - and financially - valuable bone of the whale.
An iwi representative described as "a disrespectful act of desecration".
A carved whale's tooth could go for up to $3000.
The whale was buried on the beach near where it came ashore.