Prime Minister Srettha Thavisin made a surprise visit to Suvarnahabhumi airport on Monday, and told officials to speed up immigration and baggage claim for travellers.
Mr Srettha posted a message on X, formerly Twitter, saying that passengers should to take no more than 30 minutes to go through immigration, and should also have to wait less time to collect their luggage.
Other issues that needed to improve included the IT system and its backup. It had crashed several times, he said.
His visit came ahead of planned upgrades to airports across the country, including construction of a new runway at Suvarnabhumi.
One passenger who landed on Sunday night said he and others returning from Taipei on Thai Airways International flight TG635 had to wait 90 minutes to claim their luggage.
"What disappointed me and other passengers was there was no announcement by the airport informing passengers of the cause of the delay and when they could expect to get their bags," he said. "All we could do was sit and wait."
Their flight arrived at Suvarnabhumi at 11.15pm on Sunday.