The carcass of a mysterious animal that washed up on the shores of a Philippine beach and onto social media has fueled rumours of the discovery of a new species.

Photos of the large blob, which seems covered with long white fur, were shared on Facebook by Marjorie Cabatingan Aboy on Feb 22 and promptly went viral.

It was found on Cagdianao, part of the Dinagat Islands south west of Manila.

At 6.3m long, minus its tail, it is a very large carcass.

Some suggested at first that it was a dugong, but the sea cow, though large, generally grows to a maximum of three metres.

Others were wondering if it was a new species or a sea monster.

Conservation group Marine Wildlife Watch of the Philippines said it was likely a sperm whale. But it would have to look at the skull or do an DNA analysis to confirm this, it said.

"The carcass has a total length of 6.3 metres excluding the tail which is missing and a total width of 2 metres from the dorsal to pectoral fin," said the municipal office of Cagdianao on its Facebook page.

It also said that it was a species of whale.

Dinagat's Municipal Environment and Natural Resources Office is examining the remains to confirm the species and determine the cause of its death, the post said.

But why would a whale be furry?

A netizen suggested that the hair was in fact rotting muscle fibre.

Facebook user Scott Blandzinski said: "It's a decomposing whale that died about a fortnight ago. All that white fluff is a result of it being in an advanced stage of decomposition, with the apparent hair actually being exposed, rotting muscle fibers."

The carcass is the latest in a string of unusual sea creatures that have reportedly been spotted on the islands recently, The Daily Mail reported.

Giant oarfish have been washing up elsewhere in the country.