A row is brewing between Irish farmers and suppliers of malt -- a key ingredient in beer and stout -- over the price.

Farmers are claiming there is a worldwide shortage of the malting barley which is key to the brewing process.

According to the Irish Farmers' Association (IFA), there is currently no shortage of the crop in Ireland, but if producers are not paid enough they may stop growing it.

However, a spokesman for one of the suppliers of the key ingredient -- Greencore Malt -- blamed lower prices paid to farmers on a worldwide "glut" of malting barley.

Growers are now being offered a price below what they were paid in the mid-80s, the IFA president Padraig Walshe said at a conference during Dublin Horse Show week at the RDS.

As Diageo, the brewers of Guinness, this week confirmed they are considering a price increase for a pint of the black stuff as well as for their beers, growers were being asked to take 20pc less for their barley, say farmers.

A spokesman for Greencore Malt, which supplies Diageo, said grain prices had in general "fallen dramatically" in the past few months on the continent and elsewhere.

"We have no choice but to reflect the prices," he said, pointing out that prices rose by 80pc during 2007. In 2006, Greencore Malt paid €120 per tonne to farmers, this rose to €205 last year before falling to €165 a tonne this year.

Meanwhile, at the RDS yesterday Horse Sport Ireland, the governing body for the industry, launched a new tax guide for breeders.

The sector is estimated to be worth over €400m to the Irish economy and there are 110,00 sport horses in the country, including 27,500 breeding mares.