Timber felled illegally is being used to rebuild houses in tsunami-devastated Aceh province, a conservation group said, warning the practice could create another disaster.

Unauthorised logging has increased dramatically since the December 26 tsunami disaster as demand for the wood to be used in reconstruction phase has soared, said Frank Momberg of Fauna and Flora International.

"To prevent a bigger disaster in Aceh, illegal logging must be stopped," Momberg told AFP on the sidelines of an environmental conference in the provincial capital Banda Aceh.

He said 1,000 hectares of forests in Aceh Jaya district had been destroyed by illegal logging and only a small amount of legal wood was being used in Aceh's reconstruction.

"After the tsunami, illegal logging is rampant. If this practice continues, there will be more problems. Illegal logging can cause landslides and floods," he said.

Foreign and local aid groups helping the reconstruction of Aceh are aware that they are using illegally-felled timber, Momberg said.

Countries like the United States, Australia and New Zealand have promised to supply timber to Aceh to meet reconstruction needs, but such assistance has yet to arrive, officials said.

Environmentalists have said that three decades of separatist conflict in Aceh had protected the region from illegal logging that has destroyed vast tracts of Indonesia's forests.

But they said with peace talks underway in the wake of the tsunami disaster, the region may be targeted by timber barons keen to make fast cash supplying wood for the province's resconstruction.

The tsunami killed more than 128,000 people in Aceh left another half-a-million homeless. Rehousing them involves a massive construction project requiring thousands of tonnes of wood and other raw materials.