US agriculture secretary Mike Johanns and US Trade Representative Rob Portman have criticised a Canadian decision to investigate imports of US maize.

"The United States is very disappointed by Canada's decision to proceed with a formal anti-dumping/countervailing duty investigation of imports of US corn," the two said in a statement. "We do not believe the petition contained sufficient evidence of injury to Canadian corn growers to initiate an investigation. The US Government will be actively engaged with the Canadian investigative agencies during the investigation to defend the interests of US corn producers and exporters."

"Canada conducted two prior investigations of US corn imports, revoking a countervailing duty order after a GATT panel decision was adopted in 1992 and finding no injury in a second investigation in 2001," they said. "Imports of US corn into Canada are actually down over the past two years. While Canada's corn production has increased, Canada's domestic corn demand still cannot be met through domestic production alone. Prior to the launch of this case, many Canadian corn users expressed their opposition to this case moving forward."