Ricardo Etchegaray, the country's top tax collector, said that the offices of 48 agribusiness outfits were raided by 740 federal agents and information analysts on Tuesday.

Mr Etchegaray said Cargill, Bunge, Netherlands-based Nidera SA and Hong Kong-based Noble Group were among the companies targeted in the raids.

He said that the companies involved had hidden millions in profits on grain sales by creating fraudulent documents, including nonexistent "shell" companies under the names of front men, people with few economic resources and even dead people.

The tax agency also said it had informed the Financial Information Unit, Argentina's official money-laundering watchdog, of suspicious transactions including huge cash withdrawals by large grain exporters.

The unit's president Jose Sbatella said last month in an interview that grain companies also evade Argentinian taxes by "triangulating" their exports - for example by selling grain at a below-market price to a shell company in neighbouring Uruguay before reselling it at market prices to customers elsewhere in the world.

Argentina is the world's third-largest soy exporter and second-largest corn exporter.

Argentinian President Cristina Kirchner has tried to secure a larger share of commodity revenues to support social spending through export controls and tax increases.

The raids were carried out as Ms Kirchner sharply criticised the industry during her annual address to Congress on Tuesday.

She urged deputies to impose new criminal penalties "so that evaders go to jail" and said agribusiness contributed just 2.8 per cent of the state's tax revenues last year - an amount roughly equal to revenues generated by private schools.

"Either they're charging very expensive tuition, or there's evasion in the main sector of our economy that needs to be tackled," Ms Fernandez declared.

She also proposed to limit foreign ownership of land, saying that this would "ensure our vital resources stay in our orbit."

Ms Fernandez emphasised that the law "shouldn't be anti-foreigner or chauvinistic."