Buenos Aires - Argentine farmers' unions Wednesday resumed their strident stand-off with the government, signalling an eight-day strike to block all exports of wheat and bean crops such as soya from the agricultural giant.

At issue is the government's new export tariffs on soybeans and sunflower products that prompted massive street blockades and strikes last month. The strikes were suspended during a 30-day truce to talk to the government.

Mario Llambias, president of the Agrarian Federation of Argentina (FAA), said the talks had failed, and indicated farmers would demonstrate along major highways. He did not however indicate streets would be blocked, as they were last month, when the strike emptied grocery shelves in urban areas.

Farmers are angry over the increase in the export tax on soy and sunflower products from 35 to 44 per cent, which the government says is necessary to keep more food in country and keep it affordable for Argentines. The government would also claim all money earned by farmers above 600 dollars a ton of soya.

Farmers, after years of thin harvest, are earning good income for a change as prices for exports rise along with international demand for food commodities.

An eight-day refusal to deliver crops for export would cut hugely into state revenues.

Earlier Wednesday, 15 Latin American countries met in Nicaragua to discuss "food sovereignty and security" amidst worries about soaring food prices. Riots against the rocketing costs have spread around the world. (dpa)