Budget airline Ryanair is set to close its Belfast City base on 31 October in protest at the news that a public inquiry into a proposed runway extension had been further delayed.

Michael O'Leary, the carrier's chief executive, said the decision showed "a lack of willingness on the part of local authorities" to help support growth in Northern Ireland's tourism industry.

The Northern Ireland Executive had been scheduled to determine the fate of the runway extension in 2008, with Ryanair claiming it has been unable to launch a wider range of European routes from the airport.

Ryanair opened its Belfast City base in October 2007 and operated a total of five routes to UK destinations. However, its decision to withdraw means Belfast may now lose out on 1 million passengers each year.

O'Leary said: "The reference to a public inquiry and now the further delay to the public inquiry for spurious noise reasons, shows a lack of willingness on the part of the local authorities to grow and develop traffic, routes, tourism and jobs in Northern Ireland."

Tourism Ireland chief executive Niall Gibbons told the BBC: "Tourism Ireland will continue its cooperative marketing efforts with the other carriers into Northern Ireland from the British market to help stimulate demand for holidays, short breaks and business travel."

Glyn Roberts, chief executive of the Northern Ireland Independent Retail Trade Association, added: "Air routes such as these are absolutely vital for Northern Ireland developing its tourist potential and as a location for major UK conferences. We simply cannot afford to lose them."