The Department of Conservation fears a third Māui dolphin has died this year after it was told one washed up on an Auckland beach yesterday.
The body of a juvenile dolphin was found on Karioitahi Beach in the Franklin district by members of the public who reported it to DOC.
The species is critically endangered and found only on the west coast of the North Island.
If confirmed this would be the third Māui dolphin death reported to DoC this year.
DoC marine species and threats manager Ian Angus said the dolphin appears to have been there for some time and was badly decomposed.
He said it would be unlikely a necropsy would be able to determine the cause of death, however, it would be sent to Massey University to be examined.
"If confirmed, it will be the third Māui dolphin death to be reported to DoC this year. The previous two were found to have died from natural causes," Angus said.
"It's tragic to have another juvenile dolphin die. We are hoping an examination may help us better understand why this has happened."
Earlier this year in October, a pregnant female dolphin was found dead near Te Akau, north of Raglan.
Tests showed it had died from blood poisoning after complications while giving birth.
Another Māui dolphin was found dead at Port Waikato and was found to be a victim of shark predation.
Given the number of Māui dolphin is steadily declining, Angus pleaded for people to report any sightings as soon as possible.
"We urge the public to report any sightings or deaths as soon as possible," he said.
"Every dead dolphin that can't be necropsied is a lost opportunity to understand what is threatening the dolphins."
The Department is calling for people to photograph and report any sightings of a Māui or Hector's dolphins to the emergency hotline 0800 DOC HOT (0800 362 468).
Since 2008 there have been seven recorded Māui dolphin deaths, following this latest report, DoC said.