The Competition Authority has written to Ibec over a warning by the employers' sub-group, Food Drinks Industry Ireland (FDII), that prices would have to rise because of higher business costs.

Chaired by Dr Bill Prasifka, the authority has also written to the Irish Auctioneers' and Valuers' Institute (IAVI) after it warned that estate agents' fees would have to rise because of a slowdown in the market.

The move by the authority is seen as a shot across the bows of the two representative groups and a warning to other industry sectors not to act in concert to push up prices at a time of rising inflation. A spokesman said the authority was concerned that recent public statements by the two groups could be interpreted as amounting to directions to members to raise their prices.

"Price signalling can facilitate firms who should be competing against each other to raise prices in a co-ordinated manner, thus depriving consumers of the benefits of competition," the spokesman said.

FDII had warned that food prices were likely to rise in the coming months due to "spiralling" business costs.

FDII and the IAVI have replied to the authority saying they are aware of their responsibilities under the competition Acts.

The National Consumer Agency (NCA) has expressed concern at FDII's warnings about price rises.

The agency's chairwoman, Ann Fitzgerald, told an Oireachtas committee last week that shortages of commodities or crop failures would have some impact on grocery prices. However, she said this impact should be proportional and should not become embedded into prices on a permanent basis.