Dublin Airport Authority's (DAA) attempt to increase airport charges to €7.50 per passenger has been turned down again by the aviation regulator.

The regulator, Cathal Guiomard, has decided to increase the maximum charge per passenger from €6.14 to €6.34, significantly below what the DAA wanted. It said last night it was "extremely disappointed".

The DAA claims it needs a €7.50 per passenger charge in order to fund a €1.2 billion capital investment plan for the airport. Among the items it intends to build is a new Pier D facility and a second terminal. There is also a plan for a new runway.

Mr Guiomard, who heads up the Commission for Aviation Regulation, said last night his office had yet to receive a full and detailed copy of the DAA's capital expansion plan. He said that after studying this, there might be a chance to re-visit the figures.

"The commission has commenced internal work to consider whether substantial grounds might exist to warrant a further review of the determination in the light of the DAA's anticipated capital investment programme, which we hope to receive in the near future.

"On completion of this analysis, the commission will publish a commission paper setting out its conclusions and seeking the views of interested parties on a possible review."

Last year, the regulator decided to cap the charge at €6.14, but an appeals panel set up by the Department of Transport asked him to study the matter again. Since then, Mr Guiomard's office has been re-assessing financial data from the DAA.

DAA chief executive Declan Collier said last night the regulator's decision was deeply disappointing in light of the major capital programme required at Dublin airport. "While we welcome any increase in passenger charges, it is extremely disappointing that the regulator saw fit to ignore many of the appeal panel's recommendations," he said.

"Once again the travelling public will have to deal with the consequences of a decision by the regulator that does not provide the required funds to carry out essential capital investment that will significantly improve the passenger experience at Dublin airport," Mr Collier added.

"Any investment has to be paid for, and the main way to pay for it is through airport charges."

Passenger numbers at Dublin airport are continuing to grow and will pass 20 million this year. The pace of growth is such that the Government has talked about building a third terminal in the years ahead.

Mr Collier said: "The government has mandated the DAA to build a second terminal at Dublin airport. Passengers agree that facilities need to be improved and expanded and have told us that they are willing to pay extra for such improvements."

The issue of airport charges is at the sole discretion of the regulator, although the appeals panel can ask his office to review his determinations from time to time. The Government has no direct role in the area.