Agricultural commodities prices exploded on Friday, threatening higher global food prices, after the US government forecasters slashed grains production estimates after adverse weather damaged crops worldwide.

The price movements of up to 12.5 percent were among the worst since the 2007-08 food crisis as traders scrambled for supplies amid warnings of dwindling inventories.

They followed a warning from the US Department of Agriculture that stocks of corn and barley, the feedstocks of the meat industry, would "fall dramatically" with US corn stocks forecast to hit a 14-year low.

The share prices of meat companies, which rely on cheap corn, were down. Tyson Foods fell 7.8 per cent.

The warning raised the prospect of a repetition of the 2007-08 food crisis, when the cost of agricultural commodities hit record highs and food riots rocked emerging countries.

"This revision highlights that we are in a fragile supply and demand situation," said Abdolreza Abbassian, senior economist at the UN Food and Agriculture Organisation in Rome.

"The combined shortfalls in the US, Europe, Russia and Ukraine present a much tighter supply picture than just a few months ago," the USDA said.

Traders, unable to use futures because of the daily limits, bid indicative corn prices to $5.60 a bushel in the options market, up 12.5 percent.

In Chicago, main agricultural commodities surged to daily fluctuation limits imposed by exchange rules.

European wheat prices jumped by 10 per cent while the cost of other key commodities, including soyabean, sugar, cotton, barley and oats, also surged.

The agricultural rally, coupled with stronger oil and metals prices, propelled the Reuters-Jefferies CRB commodities index to a two-year high.