The incentive comes in the form of an exemption from the 500-baht airport tax for transit passengers eligible for visa-free entry and visas on arrival.

As of October 1, they will be able to travel outside of Bangkok International Airport for up to 12 hours without paying the tax when they check in for onward flights.

The money the government loses on the tax would be more than offset if each transit passenger spent only 500 baht during a stopover, officials said.

Last year, 2.14 million passengers transited Don Muang airport. Though most of them catch onward flights within just a few hours, many spend six hours or more, which is enough for them to take a brief tour of the city.

The Association of Thai Travel Agents (ATTA) has outlined several shopping, scenery and health and beauty mini-tour programmes for tourists in transit.

"There will be things to suit all tastes," said Seree Wangpaichitr, governor of the Tourism Authority of Thailand.

"Transit tourists can enjoy tours ranging from Amazing Fruits of Thailand, Grand Sales, A Glance at Bangkok, or a scenic cruise down the Nonthaburi canal from around 1,000 baht a trip."

The ATTA will offer the tours free on October 1, the day the tax is lifted, he added.

Transit passengers who wish to leave the airport will be asked to fill out an exemption form, which they can present when they return to resume their trip.