The country's four big agro-industrial groups said they were reinstating roadblocks that have caused food shortages and rattled the four-month-old government of President Cristina Fernandez de Kirchner.

The protest also has paralysed grains exports from Argentina, a top world supplier of soy, corn, wheat and beef.

'Since farmers and livestock producers have not had an answer to their complaints ... we have decided to continue with protest measures,' the four groups said in a joint statement.

They said they would talk with the government on Monday but would not consider suspending the protest until Wednesday.

There was no immediate response from the government, which has repeatedly said it will not meet with the farmers while they are blocking transportation of farm goods.

Argentina, a land of vast, fertile plains, has hugely benefited from high international prices for commodities. But the country is torn over how to distribute windfall profits from soy and other crops.

The centre-left government's surprise announcement on March 11 of a new sliding-scale tax on soy exports, which increases levies at current soy prices, was the last straw for farmers already angry over government limits on exports to try to control domestic food prices.

Both sides dig in
President Fernandez has strongly defended the tax increase as a way to protect shoppers from the rising cost of basic food and redistribute wealth in a country where nearly a quarter of the population lives in poverty.

But the more the president has stood by the tax, the more farmers have dug in their heels and tested what critics call her authoritarian style.

When she took office in December, business leaders hoped she would try to reach consensus with them over policies instead of following in the footsteps of her husband and predecessor, ex-President Nestor Kirchner, who imposed price controls on a wide array of goods.

City residents supported farmers with three nights of pot-banging protests last week. There has not been that sort of outcry since the deep political and economic chaos of 2001-02.

During a brief truce on Friday night, farmers allowed trucks with agricultural products to circulate and began negotiations at the government palace.

After the late-night meeting, the farmers expressed disappointment with government's proposals to protect the interests of small-scale farmers and lift a months-long ban on wheat exports.

Eduardo Buzzi, president of the FAA, one of the four farm groups, said the government must suspend application of the new tax system if it expected farmers to suspend their protest.

The capital, where beef, chicken and dairy products became scarce during the week, saw some relief on Saturday morning before the protests were restarted. Hundreds of trucks that had been held up for days unloaded produce at a central market. -- REUTERS