Glanbia, the State's largest liquid milk processor, denied a claim in last night's RTÉ Prime Time programme that it was "the driving force behind a price-fixing cartel" which has cost Irish consumers millions over the years.
Prime Time claimed another large dairy processor, Dairygold, was also involved in the cartel to keep milk prices for consumers artificially high.
The programme also produced documents which claimed to show there was a "systematic operation of both the price-fixing and market-sharing cartels in the industry".
It named NCF Sligo and Oranmore as two western co-operatives which were involved with Glanbia in "market rigging", sharing out the country geographically to keep prices high.
In a strenuous denial yesterday, Glanbia, which refused to take part in last night's programme because the issue was subjudice, denied it is or ever has been part of any illegal price- fixing or other cartel.
It said the company was defending itself in civil proceedings being taken by the Competition Authority against it and other companies, arising out of a Competition Authority investigation in 1998.
Mr Ciaran Fitzgerald, director of the Food and Drink Federation of IBEC, said the allegations made in the programme did not reflect the actual changes in consumer or industry prices in the period 1995-2001.
In that period, he said, prices of milk increased by 4.3 per cent compared to general food prices, which rose by 23 per cent, and overall inflation by 18.2 per cent over the same period.
Mr Pat O'Rourke, the president of the Irish Creamery Milk Suppliers' Association, rejected the programme's assertions as "groundless" and said the real "rip off" was the totally unjustified margins being taken by retailers to the detriment of farmers.
"Based on the average CSO figures, retailers take on average 22c a litre as a mark-up, processors take 30c a litre and farmers are paid an annual price of 32c a litre for milk for the liquid trade," he said.
Mr O'Rourke said that he has called on the Tánaiste, Ms Harney, and the Competition Authority to carry out a detailed examination of the totally unjustified margins being taken by the retail sector.