The World Trade Organisation has upheld its ruling against Mexico in the soft drink row with the US.

A WTO panel has rejected an appeal by Mexico on a ruling last year which concluded that a 20% tax on Mexican soft drinks manufactured with imported high-fructose corn syrup broke global commerce rules. Drinks made with Mexican cane sugar, meanwhile, are exempt from the tax.

The 2002-imposed tax decimated US exports of the syrup to Mexico by 2004 to 6% of their pre-tax levels. The WTO panel found the tax discriminated against foreign suppliers, breaking the organisation's fair trade principles.