Ryanair is to shift the bulk of its service between Shannon and Hahn in Germany to Kerry Airport from April. The move follows a row between the no-frills airline and Aer Rianta over landing fees at Shannon.

The company is to curtail the Shannon service by operating one weekly flight on the Hahn route, down from seven at present. The service between privately-owned Kerry and Hahn will meanwhile fly every day under a 10-year agreement on fees.

Aer Rianta has expressed disappointment at the reduction in services at Shannon.

Ryanair had previously given the company until the end of this week to reconsider its position on the imposition of charges at the airport.

The airline has paid no fees on the Hahn service for the past three years, under an agreement due to expire in May. An offer from Aer Rianta to apply discounted charges for a further three years has been consistently rejected by Ryanair.

On Monday, Ryanair chief executive, Mr Michael O'Leary, wrote to Aer Rianta at Shannon, labelling the airport operator's approach "long on waffle and short on action".

Mr O'Leary dismissed Aer Rianta's argument that charges must be imposed in return for services such as heating and water supply.

"None of these costs would be reduced as a result of Ryanair's removal of this route so the decision really is within your control," he wrote.

Ryanair deputy chief executive, Mr Michael Cawley, declined to specify the charges the airline has agreed to pay in Kerry yesterday but said they were "miles below" the Shannon proposal. The new charges will include ground handling fees, costs that were payable to Servisair in Shannon.

Mr Cawley said the company did not expect to lose any passenger volume as a result of the shift. In 2002, Ryanair carried about 100,000 passengers on the Hahn route, with 84 per cent of this volume attributable to incoming traffic.

Ryanair has operated a route between Kerry and London for the past six years.

In a statement issued last night, Aer Rianta said it had "made every effort to underpin the success" of the service between Shannon and Hahn.

The company estimates that the incentive scheme due to expire in May has cost it €1.75 million.

It is understood, however, that Aer Rianta is confident of recouping any future loss of revenue due to Ryanair's partial withdrawal by concluding a service agreement with a competing no-frills airline.

It is likely that such an initiative would include flights to Germany.

A spokesman for Kerry Airport said the Ryanair move was "the biggest thing that has ever happened" at the facility.

Kerry Airport is owned by about 6,000 local shareholders, with Kerry Group one of the largest stakeholders.

The airport, which has been profitable for the last 10 years, currently offers services to Dublin and Zurich as well as London.