The Bt150-billion Suvar-nabhumi Airport will remain operational while repairs are carried out, Prime Minister Surayud Chulanont said yesterday.

"We'll do our best to ensure there is no further damage to the new airport's reputation. We shouldn't shut Suvarnabhumi down and must find a way to fix its problems while keeping it open," he said.

The prime minister's statement followed speculation by National Legislative Council member Admiral Bannawit Kengrien that the airport, opened last September, might have to be closed to all traffic to allow repairs to taxiway cracks.

According to preliminary findings of an investigation, underground water, inferior asphalt and rushed construction caused the cracks.

The investigation is headed by Airports of Thailand (AOT) director Tortrakul Yomnak.

Site tests conducted on Friday and yesterday revealed serious damage to an unspecified length of taxiway. Runways are in good condition.

"We found the runways were unaffected by seeping underground water because they are 1.75 metres higher than the underground water level, whereas taxiways are only 0.75 metres above it.

"The taxiways were built over some 2,000 fish ponds. We found underground water from elsewhere had entered the subsoil of these taxiways. The solution is to drain it off," said a committee member who requested anonymity. "Secondly, we found that asphalt used in paving the taxiways was sub-standard. Lastly, we considered the construction timetable had been too tight, resulting in sub-standard work," he said.

Panel members are divided about shutting the airport, he said, some preferring to close sections at a time. "It's now near the end of the cool-season flight schedule. Aircraft will have to change take-off and landing direction. This will allow technicians to fix parts of the taxiways and runways where there are problems," he said.

Meanwhile, Deputy Transport Minister Sansern Wongcha-um said the government would allow airlines to decide themselves if they would return to Don Muang airport while Suvarnabhumi was repaired.

"It's voluntary, and airlines cannot seek any compensation from the government for relocation costs, which means there won't be many airlines going back to Don Muang," he said.

Sansern said AOT would make a final decision tomorrow on the Suvarnabhumi repairs and the reopening of Don Muang to international traffic.