As biotech companies prepare to identify the sites of their genetically modified crop trials tomorrow, protestors and environmental activists have been warned to stay away, or face fines of up to A$10,000. People caught trespassing could also find themselves in jail, warned international biotech giant Aventis Crop Science.

GM crop trials have been conducted in Australia for some years but only now, with the implementation of the Gene Technology Act, have companies had to reveal exactly where the trials are taking place. The companies must identify the sites by way of road address and global-positioning satellite co-ordinates, and many are expecting protests from anti-GM campaigners. The first clash could occur when Aventis plants its summer GM canola crop in the South East.

Aventis and Monsanto Australia Ltd revealed yesterday that they have no plans to grow GM canola crops in South Australia this winter, preferring instead to trial the crops at interstate locations in Western Australia, Victoria and New South Wales.

Monsanto spokesman Brian Arnst added: "We are working towards a potential commercial release in 2003."