A dispute over noise pollution reports is set to delay a public inquiry into a controversial £8 million plan to extend the runway at George Best Belfast City Airport, it has been revealed.

The independent Planning Appeals Commission (PAC), which was commissioned by the Stormont government in March to undertake the probe, is refusing to schedule it until it receives further information from the airport.

The PAC claims the airport's Environmental Statement (ES) on the likely impact of the 600 metre extension is deficient and does not contain enough information about how noise levels would be affected if heavier planes were able to take off and land.

While the Government's Planning Service concedes that the ES is incomplete, it insists the statement is full enough to meet regulations. The service claims the inquiry should go ahead, with the airport providing additional information during the hearings. But the PAC is holding to its line.

"Since March 2010 the Commission has been corresponding with the Department about this major planning application," a statement on its website said on Tuesday.

"The Commission is unable to arrange the requested Public Inquiry as the information on third party representations is incomplete and it has asked the Department to address the adequacy of the Environmental Information about the application."

A Planning Service spokeswoman said officials were considering their position.

The proposal to lengthen the runway would enable planes with heavier fuel loads to use the airport, thus opening up the possibility of flights to and from further afield destinations in Europe.

But the planning application, which was first lodged in November 2008, has been fiercely opposed by some local residents living around the east Belfast facility who claim noise pollution levels will soar.

Earlier this year Environment Minister Edwin Poots set up the public inquiry to examine the contentious issue. Airport bosses have warned that further delays over the decision may risk major investments planned by international airlines.