Industrial estates in Bangkok and the East have been warned to be on alert for heavy rainfall heading towards Thailand.
Somkid Tanwatanakul, deputy governor of the Industrial Estate Authority of Thailand (IEAT), said the Meteorological Department had warned of heavy rain and strong winds in eastern provinces due to the impact of tropical storm Gaemi.
Authorities warned that estates such as Wellgrow in Chachoengsao, as well as factories in Ban Pho, Chachoengsao, and in Lat Krabang district in Bangkok, should prepare for heavy rainfall.
The Amata Nakorn estate in Chon Buri is also on alert.
Industry Ministry officials yesterday visited Ban Pho and the Bangplee industrial estate in Samut Prakan to oversee flood defences.
Bangplee will start construction of its permanent dyke next month. It is expected to be completed in June.
Mr Somkid said all industrial estates need to come up with an emergency plan that includes alert levels ranging from one to four, with four signalling the need for an evacuation.
"What happened last year, for instance, was that Lat Krabang told businesses to start halting operations but businesses did not follow the orders," he said.
Permanent secretary for industry Witoon Simachokedee said the IEAT has asked experts from King Mongkut's Institute of Technology Ladkrabang to assess construction costs for dykes.
"We have to admit that what comes out in reality is almost always different from the original plan, so we are in the process of assessing actual costs," said Mr Witoon, adding that the process will be finalised this month.
Tropical storm Gaemi is expected to weaken into a depression and enter Thailand today in Sa Kaeo province, said Somchai Baimuang, acting director-general of the Meteorological Department.
Gaemi reached Vietnam last night and is due to move on to the lower part of Laos, Cambodia and then Sa Kaeo.
The Office of the National Water and Flood Management Policy was due to assess the impact of the storm on Thailand at 1am today after Gaemi reached Vietnam and Cambodia.
Tomorrow the depression is expected to weaken into a low-pressure system that will move past the central region and proceed to Myanmar.
Mr Somchai said heavy rains of more than 100mm are expected in several provinces including Bangkok.
Royol Chitradol, head of the government's water situation assessment and management subcommittee, said torrential rain is expected tomorrow and Tuesday in Chanthaburi, Rayong, Chon Buri and Bangkok due to the effects of Gaemi combined with the impact of a low-pressure area in the Indian Ocean.
These provinces must be closely monitored for flooding, he said, adding that in inner and eastern Bangkok water-propelling boats had already been taken to most flood-prone spots to prepare for the storm.
National Disaster Warning Centre director Somsak Khaosuwan said military units in each affected area would work with other agencies to ensure public safety during the storm period.
Lertwiroj Kowathana, director-general of the Royal Irrigation Department, said the government had managed to cope well with water from the start of the rainy season by draining excess water from major dams.
These dams were being kept about 72% full to allow more room for the run-off to come during the rest of the rainy season, he said.
Bangkok Governor Sukhumbhand Paribatra said more than 400 water propellers had already been put in place for use during the storm. A centre for emergency operations has been set up to respond quickly to possible flooding in 10 flood-prone spots in the capital.