Jakarta – Indonesian environmental activists filed a police complaint against plans to build a road network through a huge conservation area in Sumatra island.

Indro Tjahyono, coordinator of the Network for Forestry Conservation, said he filed the complaint in Jakarta against Infrastructure Minister Sunarno and the governor of Aceh province, Abdullah Puteh.

The environmentalists called the road project an "environmental crime" which would violate environmental protection laws and Indonesia's international commitments.

They said it would increase illegal logging, cause erosion and landslides and damage the water supply from the area in north Sumatra known as the Leuser Ecosystem.

The European Union Environment Commissioner Margot Wallstrom last month visited the EU-funded conservation project and expressed alarm that the road network could spell disaster for it.

Indonesia's environment and forestry ministries also oppose the road plan. Work has already started on the Ladia Galaska network, which would link the west and east coasts of Aceh province and would cut through the heart of the Leuser Ecosystem.

The EU has spent 31 million euros (37.2 million dollars) on the conservation area since 1996, parts of which are a national park. The Indonesian government has contributed six million euros.

It covers 2.6 million hectares (6.4 million acres), almost the size of Belgium, and is the habitat of Sumatran rhinos, orangutans, tigers and elephants.

The 1.5 trillion rupiah (179 million dollar) road project was launched by Aceh governor Puteh, who says it will end the isolation of remote settlements.

Conservationists have put forward alternative routes which avoid the conservation area.