Thousands of Argentines are staging a march against hunger in the capital Buenos Aires.

The marchers are stopping at supermarkets and government offices to request food donations for schoolchildren.

They hope to collect 500,000 kilograms (1.1 million pounds) of food, organisers said.

Although Argentina is the world's fifth-largest exporter of agricultural produce, more than half the country's 36 million people are living in poverty, and hunger has become a serious problem.

The march - by people known as piqueteros, or "picketers", after the pickets they have been using to block roads around the country - is intended to be peaceful, organiser Raul Castells said.

"We are pacifists, but what happens later depends on the government," he told the Argentine newspaper Clarin.

He said the demonstrators would march to Plaza de Mayo, a central square.

Export market

Argentina - one of the richest countries in Latin America until recently - has had a very successful harvest this year, but farmers prefer to export their produce so they will earn dollars rather than Argentine pesos.

During the 1990s the Argentine currency, the peso, was held at a rate of one to one with the US dollar.

The peso lost two-thirds of its value

But at the end of last year, market pressure forced the government to allow the peso to trade freely, and it quickly fell to more than three pesos to the dollar.

As agricultural exports are priced in dollars, farmers now find it lucrative to export and are reluctant to sell on the domestic market.

As a result, the price of a basic weekly shop surged by a staggering 64.7% in the first seven months of this year.

With unemployment running at 22%, many families are finding it hard to pay those prices.

Each week piqueteros blockade main highways into Buenos Aires in protest at lack of work.

They have negotiated a small state benefit of 150 pesos ($40) per month for unemployed family heads.