Soldiers from the Bangkok-headquartered First Army Area are defending eight central provinces against flooding, the Army announced on Sunday.
Troops were deployed Sunday to work with government agencies and volunteers to strengthen flood defences and aid victims in the Chao Phraya basin, said the Army press release.
Army chief Gen Narongphan Jitkaewthae ordered the operations earlier this week as tropical storm Noru lashed Thailand with heavy rain and floods.
The Army said troops were deployed to clear canals and drainage channels in eight provinces, including Bangkok, Pathum Thani, Nonthaburi, Ayutthaya and Prachinburi.
The troops also reinforced embankments along major rivers to prevent flooding of communities and key roads, while helping residents to move their belongings upstairs.
In Ang Thong and Ayutthaya, troops are building sandbag walls to protect communities on the Chao Phraya riverbank.