Aer Lingus chief executive Mr Willie Walsh opposes plans by Aer Rianta for the new Pier D at Dublin Airport because it is too expensive and will increase the cost of using the airport.

Ryanair, FLS Aerospace - which owns the former TEAM maintenance business - and a residents' group in Portmarnock have all lodged official objections to the new pier with Fingal County Council. The facility will provide nine new contact stands for planes at a cost of around €70 million.

"Pier D is too expensive and does not represent value for money," Mr Walsh said. "It is clear that it will drive costs at Dublin Airport up. It's hard to quantify at this stage by how much but what we have asked Aer Rianta to do is to quantify how the operating costs would be affected."

Mr Walsh said he would welcome a new privately run second terminal at the airport.

But Aer Rianta chief executive Mr John Burke told a seminar on the future of aviation in Ireland yesterday that a privately financed terminal built specifically for low-cost airlines - as favoured by Ryanair - is probably not financially viable. Budget carriers rely heavily on rapid turnaround of aircraft and high levels of passenger throughput, and as a result the level of service they demand is equal to or greater than that required by traditional airlines.

Companies that had constructed and operated low-cost terminals at airports in Europe and North America were unable to offer discounted rates to airlines and had struggled to turn a profit, he said.