A 45-tonne sperm whale that washed ashore north of Kaikoura had part of its jaw removed by thieves.
The male whale was spotted floating out at sea, near Clarence, last week and later washed up on the shore.
Department of Conservation (DOC) ranger Mike Morrissey said the dead whale was fenced off by contractors.
However, thieves broke through the barrier and stole part of the whale's jaw.
The theft was illegal and greedy, he said.
The remaining section of the jaw was removed by DOC staff and buried. It will be dug up later and given to local iwi.
The 14.5-metre whale - the maximum size for a sperm whale is 18m - had distinctive markings on its tail.
Photographs and DNA samples have been sent to Otago University where a database is held and they will determine whether the whale was known to the area.
Whale Watch Kaikoura will be informed once the whale is identified.
Morrissey believed the whale was likely to have died of natural causes.
"It probably came ashore because of those big swells and easterly winds we have been getting recently," he said.
"I'd say it had been dead for about two weeks by the time it washed up."
The whale has been buried deep in the sand at the low-tide mark by contractors using diggers.
- The Marlborough Express