Smoke forced air traffic controllers to cancel landings in Buenos Aires [AFP]

Fires allegedly set by cattle ranchers and soybean farmers on Thursday have sent clouds of smoke across Argentina's capital disrupting air and road travel and choking Buenos Aires residents for the past two days.

Florencio Randazzo, Argentina's interior minister, said about 70,000 hectares have burned over two days, an area the size of Brussels, Cape Town or Tehran.

"[The smoke] has caused highway accidents in which nine people have died in the last few days, and more than 50 people have been seriously injured," he said on Friday.

"There has been a huge amount of environmental damage... There are some 60,000 hectares burning in the Entre Rios province and some 8,000 hectares burning in the Buenos Aires province.

"As for the smoke's effect on health, some municipalities have measurements that show a high level of carbon monoxide in the air."

On Thursday, the interior minister said Argentina was facing "a disaster caused by the hand of man".

Fire starters

On Friday, smoke drifted across the River Plate
into neighbouring Uruguay [AFP]
Officials have accused farmers of setting the blazes as a cheap way of clearing scrub from cattle-grazing land.

Cristina Fernandez de Kirchner, Argentina's president, urged the authorities to prosecute offenders.

"These fires are the result of two aspects of human nature: irresponsibility and irrationality," she said.

The smoke forced air traffic controllers to cancel landings at airports in the capital, Buenos Aires, and led police to close some major highways. Some bus routes were scrapped for lack of visibility.

The authorities reported a steep increase in the number of people seeking attention at hospitals with eye problems.

Randazzo said firefighters were coping with 300 separate grassland fires, some of which needed firefighting aircraft assistance.

Uruguay haze

By Thursday afternoon, the smoke drifted across the Plate river into neighbouring Uruguay, 223km east of Buenos Aires, causing delays in three airports.

Haze hung over the Uruguayan capital, Montevideo, the coastal resort of Colonia, and the beach resort Punta del Este, the Uruguayan navy said.

The National Institute of Farming and Livestock Technology blamed the fires on farmers clearing land for more profitable soybean crops, Argentina's chief export.

It also called them irresponsible for not seeking professional advice.

Randazzo said an investigation was under way to lay charges for environmental damage and health risks.