Police yesterday began closing 14 roads around Government House to traffic for fear that anti-government protesters may move their rally to the area.
The move came as an anti-government group threatened to hold a large rally and a nationwide strike.
Checkpoints were set up along perimeter roads and only people who could prove that they worked or lived in the area were allowed to pass, according to Metropolitan Police Bureau spokesman Maj-General Adul Narongsak.
Road closures began at 2pm yesterday, he added.
"Vehicles and people are not allowed to enter the area, unless they get permission from authorities.
People who live and work in the area must show their ID cards as proof," said Adul, who is also a Metropolitan Police Bureau deputy commissioner.
He said police intelligence showed that the anti-government protesters - now gathering at Lumpini Park and Urupong Intersection - were planning to move to Government House, which is off-limits to protesters under the Internal Security Act (ISA) invoked last week.
The government's Centre for Administration of Peace and Order (CAPO), which enforces the ISA, yesterday issued an order prohibiting the use of sections of 14 roads: Ratchasima, Phitsanulok, U Thong Nai, Likhit, Rama V, Sukhothai, Ratchavithi, Ratchadamnoen Nok, Look Luang, Phichai, Nakhon Sawan, Sri Ayutthaya, Nakhon Pathom and Krung Kasem.