Nearly a fifth of wood imported into the EU has been harvested illegally or comes from suspect sources, mostly in Russia, Indonesia and China, according to a report by the environmental group WWF.

In all, 40 per cent of wood-based products from southeast Asia, 30 per cent from Latin America and over 36 per cent of those from Africa originated from illegal or suspect sources, said the report on 2006 imports.

Major importers were Finland, Britain, Germany and Italy, it added. "Illegal logging destroys the protective function of forests, increasing the risk of natural disasters such as floods and landslides, and leads to deforestation, one of the main causes for climate change," said WWF forestry campaigner Anke Schulmeister.

The report said illegal timber hit local economies by pushing down timber prices, and called for tough EU action to clamp down on the trade.

The EU's executive body will adopt proposals in September aimed at curbing the trade by demanding certificates proving timber imported into the EU is legally harvested.