Mexico is considering modifying its contentious taxes on soft drinks using corn syrup so that they only apply to producers using imported supplies of the sweetener, sources in Mexico have said.

The change would upset further US producers of high fructose corn syrup (HFCS), who have already objected to the tax in its present form.

Mexico has argued that US imports of HFCS were stealing business from Mexican sugar growers by undercutting them with exports that were tantamount to dumping.

Since the tax came into effect Mexican soft drink producers have been switching from HFCS to sugar to avoid the higher tariff.