A number of 123 bank branches were closed as of 3.30pm, according to the Bank of Thailand.
Over half, 76, belong to TMB Bank. Krungthai Bank closed 16 branches.
Thai shares weakened Monday, as anti-government protesters seized many areas in Bangkok since Sunday night.
The Stock Exchange of Thailand index at 11.17am lost 6.42 points or 0.51 per cent, to 1,249.03 points. So far this month, the index has lost 3.3 per cent.
The Thai baht remained steady at 33 against US dollar.
The Bank of Thailand on Monday operates from its emergency centre, as staff may find it difficult to access the headoffice at Bang Khumphrom Intersection. Its note printing operations will also temporarily moved to Krungthai Bank's Pinklao Branch. Its Call Centre 0-2283-5353 remains open as usual.
As of 11am, 45 bank branches have been closed, according to the Bank of Thailand. Fourteen of them belong to Krungthai Bank; 6 to LH Bank, 5 to Siam Commercial Bank and 4 each to Bangkok Bank, Bank of Ayudhya and Kasikornbank.
Krungthai Bank closed 14 branches on Monday including those at Energy Complex building, Revenue Department, TOT Chaeng Wattana, and Union Mall Latphrao.
CIMB Thai Bank also cancelled the press conference scheduled for tomorrow. It plans to launch a new campaign to mark the Chinese New Year.
While Siam Centre and MBK Centre open as usual, CentralWorld announced that it would be opened at noon and closed at 8pm, citing difficulties to access.
The Land Transport Department's headoffice in Chatuchak is closed today. The department urged all to contact its office in Nonthaburi.
The "Bangkok shutdown" has affected over 1 million people, according to a Thai PBS report. It estimated that 680,000 residents living in and near the rally sites are affected. On top of this are 440,000 students and 1.2 million people who work in the area. The shutdown have also afffected 4.8 million transport trips.