A dead whale that has washed on to the shore of Taranaki is thought to weigh about 100 tonnes and is unlikely to be moved from its final resting spot.

The 19.5m whale washed up on Tapuae Beach, near Okurukuru, and is believed to be a blue whale or a pygmy blue whale.

Taranaki Department of Conservation acting senior biodiversity ranger Callum Lilley said it had been an interesting opportunity to get a closer look at the largest species on earth.

"It's fairly interesting, but a bit sad at the same time."

Experts from Massey University were at the beach today to carry out a necropsy.

Photo / Hemi Sundgren

"However, once inside we realised it's really decomposed inside. Although on the outside it appears it's fairly intact, it was just about like soup inside," Mr Lilley said.

He said there was nothing they could ascertain about the cause of the whale's death, except that there were no obvious signs of trauma.

Mr Lilley said because of the massive size of the whale it would likely be left on the rocks at the beach.

Photo / Glynn Hills

"Considering its size and the machinery you'd need to move it you could do a bit of damage to the beach and the rocks [if the whale was to be moved]."

The rocks where the whale has washed up are far away from any easily accessible parts of the beach, Mr Lilley said.

DOC received reports on Sunday from commercial fishermen and a ship leaving Port Taranaki of a dead whale floating close off the coast.

Mr Lilley believed it may have been on the beach since Tuesday.

Photo / Callum Lilley

Blue whales are known to feed on krill off the South Taranaki Bight.

Local iwi have blessed the whale carcass.

The public have been warned to steer clear of the carcass, because of potential health risks through transfer of disease and presence of bacteria.

There was also a health and safety risk due to heavy sea conditions and rising tides, they said.

Photos: Paddle boarding with orca

Gallery

Paddleboarding with orca whales at Kawau Island

- APNZ