"We are still investigating the report about the road. APP doesn't have anything to do with illegal activities and we are checking the legality of our wood supplies," Aida Greenbury, director of sustainability at APP, said by telephone.

According to Eyes of the Forest, the logging highway could have a devastating effect on Kampar's peat forests, one of the largest of the contiguous tropical peat forests which act as the planet's biggest carbon store.

"Drainage and plantation development activities on the top of the Kampar peat dome could even cause the peat dome to collapse and emit large amounts of carbon," Eyes of the Forest said in a statement.

It said the Kampar peninsula area is also home to around 60 Sumatran tigers, the most critically endangered of the world's tiger subspecies. There are an estimated 400-500 Sumatran tigers left.

Eyes of the Forest coordinator Nursamsu said in the statement that their investigators had come across tiger tracks along the logging road last month.

"But the tigers of Kampar don't stand a chance once APP begins logging full-scale and the poachers discover there's easy access to this critical tiger habitat."

Greenbury of APP said its policy on wood supplies was one of the most stringent in the world and complied with the law.

"We listen and have an open door policy to any input given by any stakeholders including NGOs. We haven't got any information regarding this allegation."

Green groups have frequently accused APP of destroying natural forest in Indonesia, accusations denied by the firm.

According to Greenpeace, Indonesia had the fastest pace of deforestation in the world between 2000 and 2005, with an area of forest equivalent to 300 soccer pitches destroyed every hour.

Trees store carbon dioxide, the main greenhouse gas, as they grow and emit it when they burn or rot. Peat swamps are also big natural stores of carbon.

APP is one of the world's leading pulp and paper companies with combined pulp, paper and packaging capacity in Indonesia of more than 7 million tonnes, according to its Web site.