Aer Arann has suspended its flights from Belfast to Dublin because of low passenger numbers.

The company says the service achieved an average flight load of only 11 per cent since it was launched in June.

At the time of the launch, the company predicted that 40,000 passengers would be flying the route within 12 months. These figures were partly based on the high numbers of people - one million by rail and two million by bus - that travel between the cities each year.

Aer Arann commercial manager Ms Jennifer Mooney told The Irish Times that the service was indefinitely suspended because predicted "passenger traffic did not materialise".

The route was expected to appeal to business customers on both sides of the Border and its implementation was strongly encouraged and supported by trade organisations, including the cross-Border body, InterTradeIreland.

The service, which will cease next Monday, is the only one that operates between Dublin Airport and Belfast City Airport. Prior to its introduction, no aircraft had flown the route since 1995.

Ms Mooney said the flight price had already been cut since the launch of the service - a reduction of £10 to £50 sterling for a return flight (or €60, if flying from Dublin) - and it had been heavily promoted in each city. In fact, the price of a return flight was now cheaper than the cost of a train ticket. It would not have been feasible for Aer Arann to reduce prices any further.

She added that this was a fully commercial service. Unlike some other Aer Arann routes - to Donegal, Knock, Sligo, Galway and Kerry - there was no Government subsidies to operate it, nor had the company applied for them.

Asked why the route had not achieved its target, Ms Mooney suggested the service may not have been taken up by rail passengers because they had become too used to travelling by train. There may also have been a perception that flying between the cities took longer than using other transport methods.

She said Aer Arann was not the first airline to fail to make the Dublin-Belfast route a success.

Meanwhile, InterTradeIreland expressed its disappointment at the news of the suspension.

"We understand the commercial reasons for suspending this service," said Mr Liam Nellis, its chief executive, "but we are hopeful that at some point in the future it may be reopened.

"We will continue with our work in looking for opportunities that open the island for trade and delivering initiatives that bring benefits to both economies."

Although the company was suspending the service, Ms Mooney said Aer Arann would continue to monitor the route to see if a case could be made for its reinstatement.