Suvarnabhumi Airport on Saturday opened eight automated immigration lanes for foreigners, but only Singaporeans will be allowed to use the system initially.
The automated passport control (APC) system has been available for Thai nationals since 2012 and more than 20 million have used it, said Immigration Bureau commissioner Nathathorn Prousoontorn.
After evaluating the system, he said, the bureau decided to make it available to foreign visitors in order to speed up immigration clearance, reduce the burden on staff and cut the waiting time in queues.
The decision was a response to growing public dissatisfaction with service at the capital's two international airports. Both are run by Airports of Thailand Plc, which is listed on the Stock Exchange of Thailand and is one of the most profitable state enterprises.
That dissatisfaction turned to outrage earlier this month when passengers faced four-hour waits after a number of delayed international flights arrived simultaneously at Don Mueang airport.
In the initial stage at Suvarnabhumi, two automated gates will be used only for Singaporeans, about one million of whom visit Thailand each year for tourism and business, some as repeat visitors.
Mr Nathathorn said the decision was based on an analysis of security and on a reciprocal agreement, as Singapore was now considering allowing Thai nationals to use its automatic gates as well.
Nationals of Hong Kong may become the second group of foreigners allowed to use the system, he said.
The automated immigration gate has a system to record passenger information and fingerprints for identification on subsequent trips. It can also be linked to airlines' check-in systems to verify passengers' identities.
The bureau will consider using the system at other airports including Don Mueang, U-tapao and Phuket.
While most complaints recently have focused on inadequate staffing of immigration counters at Don Mueang airport, Suvarnabhumi is also stretched to the limit on some days when many flights arrive in a short time.
Pol Lt Gen Nathathorn said the bureau had made more officials available and had expanded the immigration hall at Don Mueang to process more passengers. More officials will also be stationed at Suvarnahumi as well as the high season for tourism is approaching.
The bureau has a target of one minute per passenger for immigration clearance and is aiming to bring services into line with international best practices, he added.