More than 1,000 barbecue fanatics in Uruguay have grilled up 12 tonnes of beef, setting a new Guinness world record while promoting the country’s succulent top export.

Army personnel set up a grill nearly 1.5 kilometres long and firefighters lit six tonnes of charcoal to kick off the gargantuan cookout.

Some 1,250 people grilled the beef and about 20,000 spectators cried with joy when a Guinness judge confirmed the barbecue record had been broken.

"I’m very proud to be Uruguayan. We have the best beef and now we have the world’s biggest barbecue," said one of the volunteer cooks, sporting an apron and chef’s hat.

The South American country bested a Mexican grilling record from 2006 by a resounding 4 tonnes.

The barbecue was organized by the National Meats Institute, or INAC in Spanish, which tracks beef sales abroad.

Beef exports raked in $US817 million ($88s million) last year for Uruguay, a laidback country of some 3.2 million people squeezed between larger neighbours Argentina and Brazil, also major cattle producers.

"Uruguay is very small, it’s not known for other events so we have to use these kinds of gimmicks so people find out where Uruguay is and what it has to offer," said INAC’s vice president, Fernando Perez Abella.