Wheat prices in the US and Europe hit their highest levels in more than a decade yesterday as drought and floods continued to threaten harvests in grain-producing regions across the globe.

The weather problems come at a time when global wheat stocks are expected to shrink to a 30-year low.

French wheat futures hit their highest level since the contract was launched in 1998, rising 4 per cent to €181 before easing back to €179.25. In Chicago, July wheat prices jumped 28½ cents to $6.18 a bushel, an 11-year high, gaining 33 per cent since the start of April after heavy rain added to fears of a poor harvest.

"You had a beautiful wheat crop . . . that got nailed with frost, and now you're getting rain when you're trying to harvest it," said Jerome Leman, broker at Wellington Commodities.