Engineers are currently working to repair hundreds of cracks that have appeared in the runways and taxiways.
The cracks have forced authorities to close parts of the airport, including several airbridges used to transfer passengers to and from aircraft.
The government says the problems were caused by design flaws and alleged corruption during the airport’s construction and are not a safety issue.
The government plans to reopen the capital's
old airport at Don Muang [Reuters]
Thai Airways was the first to say earlier this week that it saw no need to divide its international flights between two airports.
It said the move could prove confusing to travellers and seemed unnecessary, since Suvarnabhumi was "safe for operation."
In its own statement on Friday Star Alliance said its members "fully endorse" the decision of Thai Airways and all its members have signalled their intention to stay "under one roof at the new Suvarnabhumi Airport."
Nine of Star Alliance’s 20 member airlines fly to and from Bangkok.