THE COMPETITION Authority is investigating a complaint made by Aer Arann against Ryanair alleging predatory pricing on daily flights between Cork and Dublin.

Ryanair confirmed that the Competition Authority, which is led by former aviation regulator Bill Prasifka, has made contact with the airline.

"Ryanair will be responding in due course," a spokesman said.

The airline said there was no substance to the complaint. "We assume it is designed to deflect attention from the €100 million that Aer Arann has received in subsidies on the PSO [ public service obligation] routes in the past six years and the nearly €50 million that it is looking for over the next few years," the spokesman added.

No comment was available from either Aer Arann or the Competition Authority.

The Cork to Dublin service is the busiest domestic air route in the country, with 497,000 using it last year. Aer Arann accounted for about 150,000 of these and Ryanair the balance.

The 30-minute flights are popular with business people and Cork-based passengers using Dublin as a hub to other destinations.

It is understood that the complaint was lodged recently by Aer Arann, the regional airline headed by Padraig Ó Ceidigh.

Aer Arann recently axed two daily flights from Cork to Dublin and now flies five times a day between the airports. It has faced intense price competition from Ryanair since Michael O'Leary launched the service in 2005.

Ryanair also offers five services a day on the Cork-Dublin route, although it uses larger aircraft than Aer Arann.

Analysts have questioned whether either airline is operating profitably on the route, given the price competition involved and the current high price of oil.

A search of both websites revealed that all of Ryanair's seats on the route are priced at just 99 cent while Aer Arann's lowest quoted fare is €8.70. Neither price includes fees and airport charges.