The Canadian government has added to the growing pressure on the US to slash the subsidies it pumps into its food sector, formally requesting that a World Trade Organisation (WTO) panel declares that Washington's largesse has been illegally high.

The chairman of the ongoing WTO Doha Development Round has already called for the US to reduce its subsidies below the US$19 billion allowed annually following the last Uruguay Round, and now Ottawa is claiming the US broke that limit anyway in 1999, 2000, 2001, 2002, 2004 and 2005.

If Canada wins the case, it would open the way for other countries to demand the US cuts its subsidies (Argentina and Nicaragua are already considering joining Canada in the case), and retaliatory trade measures could be authorised against the US by the WTO.

"These violations nullify or impair the benefits accruing to Canada" under the WTO's agriculture agreements, said a Canadian statement.