Chalit, chairman of the organising committee for the celebration, said after a committee meeting on Friday that two major issues were involved in the delay.

Security has become a hot topic following complaints from female airport staff of sexual harassment, and noise pollution continues to affect nearby residents.

Noise could be solved by adjusting flying techniques on approach and takeoff, he added.

With these problems still to be solved, the airport is not ready for an official opening for another six months, in a ceremony to be presided over by His Majesty the King. All problems must be solved before then, he said.

The committee meeting also instructed Airports of Thailand to improve security ahead of next June. That is when International Civil Aviation Organisation officials are due to inspect the airport ahead of issuing ICAO certification.

Friday's meeting was the committee's ninth and final get-together, Chalit said, adding that he would make a public announcement of problems encountered by the airport

during its first 51 days of operation.

Meanwhile, national police deputy commissioner Isaraphan Sanitwong na Ayutthaya urged female staff to file complaints so legal action could proceed over claims of sexual harassment.

He said rumours of deaths and people going missing from the airport were untrue.