KUALA LUMPUR - Sand dredging in a Borneo wildlife sanctuary is threatening the habitats of endangered pygmy elephants and a rare species of monkey, Malaysian activists said Thursday.

Sand-laden barges were once again moving up and down rivers in the Kinabatangan wildlife sanctuary in Sabah state on Borneo island, despite having previously been stopped, they said.

Harjinder Kler from the Hutan environmental group, said the erosion caused by the dredging would affect about 200 pygmy elephants and a few hundred proboscis monkeys living in the sanctuary.

"It will cause more and more of their habitat to be eroded and polluted as a result of the siltation from the dredging," Kler told AFP.

As the Kinabatangan river feeds into the Sulu Sea, she said the silt from the dredging would also pollute the Coral Triangle - a global centre of marine biodiversity spanning Malaysia, Indonesia, the Philippines, Papua New Guinea,

East Timor and the Solomon Islands. Most sand dredging works were halted following the creation of the Kinabatangan wildlife sanctuary in 2005, a 64,000 acre area in the north of the state.

Sabah state tourism, culture and environment minister Masidi Manjun said he was surprised that new permits were issued to sand dredging companies and promised a full probe.

Masidi said he had last week urged the oil palm industry to donate land along the Kinabatangan riverbank for conservation.

"I am very disappointed that such a thing has happened as we have been talking about creating a corridor of life for the wildlife on both sides of the river and this dredging will destroy all our hard work," he added.

Pygmy elephants on Borneo form a sub-species of the Asian elephant. The creatures have a rounded appearance and are smaller than their mainland cousins.

Authorities say there are around 1,500-2,000 left on Borneo island.

The Proboscis monkey is mainly reddish-brown, with grayish limbs and has a distinctive large protruding nose, from which it takes its name.

It lives in the island's mangrove forests, swamps and jungles but habitat loss and poaching have seen its numbers in the wild dwindle to around 1,000.