A Swedish-born tycoon who acts as a deforestation adviser to British Prime Minister Gordon Brown has stirred up controversy in Brazil for reportedly claiming all the Amazon could be bought for $US50 billion ($52 billion).

Johan Eliasch, the 46-year-old boss of the Head sports equipment company, is under investigation by Brazilian police and intelligence services for the alleged comments and for 160,000 hectares of Amazon forest he is believed to have bought, the newspaper O Globo reported on Monday.

He reportedly made the assertions to stimulate land acquisition as part of his role as director of Cool Earth, an organisation he co-founded which finds sponsors for the rainforest as a way of protecting it.