Tensions are mounting in Argentina as president Cristina Fernadez attempts to turn public opinion against farmers, who are now into their third week of strikes.

The unrest was triggered last month when the government introduced a new sliding scale of export taxes on commodities such as wheat, beef and soya. For example, soybean taxes were increased from 35% to 45%, as the government attempted to boost its revenue in the wake of booming global commodity prices and a sliding Peso.

But the move has angered farmers, who believe the government is profiteering. They have set up road blocks and refused to supply grain terminals and cattle markets for the past three weeks.

According to one farmer who contacted Farmers Weekly this week, the 54 auctioneering companies who operate at the Mercado de Liniers stockyard in Buenos Aires still have no cattle to sell and supermarket shelves are running empty. Grain and beef exports are seriously affected.

But addressing a rally of over 20,000 supporters on Tuesday (1 April), President Fernandez accused farmers of holding the country to ransom. She compared the three-week protest to the situation in 1976 when farmers had created national food shortages. This was just before Argentina's "worst tragedy", which led to a coup and seven years of military dictatorship.

She has also denounced farmers for striking at a time of relative prosperity, contrasting their "protests of abundance" with the "protests of poverty" in the early 2000s, when thousands of Argentines lost their savings in the 2001 financial crisis.

Farmers groups said they were considering their position after the speech, but denied they were "coup plotters", according to wire service reports.

Earlier this week they had rejected a government compromise, which offered to some rebates on the export taxes for smaller farmers, transport subsidies for farmers a long way from markets and credit plans for dairy farmers.

Meanwhile, President Fernadez has cancelled a planned trip to London, to deal with the crisis at home.