BANGKOK (Reuters) - Thailand's prime minister called for all agencies to collaborate to protect the capital from a potential deluge of floodwater on Saturday as thousands scrambled to protect homes and two more industrial estates now in danger.

Thailand's worst flooding in half a century has affected a third of the country and has threatened to hit Bangkok for several days and Yingluck Shinawatra's government was pinning its hopes on diverting floodwaters around the city into the sea.

The military said it was struggling to protect the Lat Krabang and Bangchan industrial estates to the north and east of Bangkok, risking more disruption to supply chains and cuts in production for foreign firms operating in the country.

Bangkok was clear and sunny for a second day on Saturday, but the threat of heavy rain still loomed large, with most defense walls holding, for now, and canals and the Chao Phraya River already full to the brim.

Walls of sandbags failed to hold off water in some northern Bangkok districts, like Lak Si, where many homes were flooded and people waded in waist-high waters or pushed stalled cars through streets. More than 113,000 people in affected provinces had taken refuge in 1,743 shelters.

"The water is coming close to Bangkok," Yingluck said in a televised address on Saturday.

"All agencies have to be united where tackling the runoff is concerned, because successfully diverting the water to drain into the sea via east Bangkok would hinge on all relevant agencies moving in a concerted effort."

Twenty-eight of Thailand's 77 provinces and 2.46 million people are affected, with water covering an area 16 times the size of Hong Kong.

The floods have killed at least 356 people since July and devastated seven industrialized areas north of Bangkok, inflicting damage estimated at least $3.3 billion and putting more than 650,000 of Thais temporarily out of work.

Myanmar has suffered at least 100 deaths and Cambodia 247 as a result of severe flooding.

Thailand's central bank said 2011 growth might be about 3 percent rather than the 4.1 percent it had previously forecast. The finance minister forecast growth in Southeast Asia's second-biggest economy might be barely 2 percent this year.

Residents moved valuables to higher ground, thousands of cars were left at parking lots at shopping malls and concert venues, while some vehicles were moved to bridges and flyovers.

Stores ran out of bottled water and instant noodles. People were seen buying sacks of ice to melt into drinking water.

An airport in northern Don Muang area was transformed into an evacuation center, with 3,000 people sleeping in departure lounges or tents pitched in the arrivals hall. There was no disruption to flights at either of the city's two airports.

The crisis has become a major test for the politically-inexperienced, 44-year-old Yingluck, whose government has been widely criticized for mismanaging the crisis and sending conflicting signals to the public.

A week ago, the government said Bangkok was in the clear. Now, it is warning residents to prepare themselves.

One obstacle for Yingluck is her reliance on political rivals in the Bangkok Metropolitan Authority and the military, with which her ruling Puea Thai Party has strained ties, to protect the city and regulate water flowing through sluice gates, estimated at 8-10 million cubic meters a day.


Yingluck said it was vital the government and city authorities acted as one, instead of criticizing each other.

Scattered rain was expected on Sunday and Monday, according to the Meteorological Department.

Bangkok has so far escaped the full force of the flooding, with fringe provinces of Ayutthaya, Pathum Thani and Nonthaburi among the worst hit and seven industrial estates closed. Water levels there were as high as two meters and people were seen packed into boats.

Air force helicopters transferred patients from Bangkok hospitals seen as potential danger spots while troops battled to protect Lat Krabang and Bangchan industrial zones.

"We won't leave the job but we can't guarantee you 100 percent that they won't flood," army chief Prayuth Chan-ocha told reporters, adding that he ordered troops to reinforce floodwalls and raise their height.

Lat Krabang is home to 254 factories and Bangchan has 90 facilities. Both are responsible for autos, transport, food and beverage and electrical appliances industries.

Forty-nine factories at Lat Krabang are Japanese, including Honda. It also houses plants operated by Isuzu Motors and Unilever.

The potential economic damage from serious flooding in the city of at least 12 million people is huge, with Bangkok accounting for 41 percent of gross domestic product.

Japanese car makers have suffered badly, with output slashed by about 6,000 units a day, while tech giants like Intel, Apple and Dell could be affected as a result of a cut in Thai production of hard drives.

Traders also estimate about 2 million tonnes of milled rice may have been ruined in Thailand, the world's top rice exporter.

(Additional reporting by Angie Teo, Panarat Thepgumpanat and Aukkarapon Niyomyat in Bangkok and Prak Chan Thul in Phnom Penh; Writing by Martin Petty; Editing by Sugita Katyal)

Mochila insert follows.