Thailand's worst flooding in at least five decades forced the closure of seven industrial estates in central provinces from October last year, causing billions of dollars of damage and putting about 650,000 people temporarily out of work.

Many factories have still not reopened but industrialists are already worrying about the next rainy season, barely four months away, and want the government to start acting on specific, concrete plans rather than outline broad ideas.

"We still have faith in the government and what they're trying to achieve," said Setsuo Iuchi, president of JETRO Thailand, the local arm of Japan External Trade Organisation.

"I rather believe that people want to be here and keep on investing but, yes, we can't deny that more clear-cut actions by the government have to be made."

Companies like Hana Microelectronics Pcl HANA.BK and Aapico Hitech Pcl AH.BK, whose plants were inundated, have called on the government to come up with both short-term remedies and long-term solutions to prevent future floods.

Only one or two companies, such as U.S.-based chip maker ON Semiconductor Corp (ONNN.O), have said they are closing facilities completely after suffering from the floods.

Some big names have announced sizable investments to either restore old plants or build new ones.

This week alone, Toyota Motor Corp (7203.T) said it would spend 8.2 billion baht to build a new plant and restart one closed in 2010 , and fellow Japanese firm Minebea Co Ltd (6479.T), a bearing maker, said it would invest $75 million to build a new plant.

PLAN TAKES SHAPE

Deputy Prime Minister and incoming Finance Minister Kittirat Na Ranong outlined water management plans last weekend involving seven projects, including flood prevention measures along the Chao Phraya river that flows from the north and through Bangkok.

It involves reforestation, the construction of dams and reservoirs and city planning. "We have to move quickly. This cannot wait," he said.

One of the seven projects is a 10 billion baht plan to plant trees and build dikes along upstream tributaries of the Chao Phraya. Another, costing 50 billion baht, involves the construction of reservoirs in the river basins where the floods developed.

Other projects include the building of floodways in 2 million rai (800,000 acres) of farmland plus irrigation systems, the cleaning-up of canals and waterways and establishing a data system for water management.

Some 120 billion baht is earmarked for the construction of floodways and flood diversion channels, with work this year involving the improvement of dikes, sluice gates and canals.

"I'm not that confident these projects would work," said Chaiyuth Sukhsri, head of the Water Resources Engineering Department at Bangkok's Chulalongkorn University.

"The time period for formulating this plan is very, very short. It usually takes a lot of time to analyse these things," he said, adding that the social impact of the plans seemed to have been ignored completely.

Even so, Chaiyuth noted that rains could be heavy this year because of the La Nina effect.

Some analysts say erratic climate patterns are complicating things for policymakers.

For example, it is becoming more difficult for dam managers to make judgments based on previous weather patterns. Water discharged too late and in huge volume from northern dams was, for some analysts, a big factor behind the disaster last year.

DIKES AROUND ESTATES

Last week the Industrial Estate Authority of Thailand IEAT.L, under the Ministry of Industry, outlined a plan to build permanent dikes up to 6.5 metres (21 feet) high around the seven industrial estates forced to shut by floods last year.

"We now have a plan for building a permanent dike designed by the Engineering Institute of Thailand using statistics of flooding events in the past 100 years," Vithoon Simachokdee, permanent secretary of the Ministry of Industry said.

Each estate will adapt the proposed dike to its own circumstances and can apply for loans from the Government Savings Bank, which has a credit line of 15 billion baht offering loans at 0.01 percent over seven years.

The aim is for the work to be completed in August, Vithoon said.

Kobkarn Wattanavrangkul, chairwoman of Toshiba Corporation's (6502.T) Thai unit, said the Bangkadi industrial estate, of which she is also chairwoman, would have a dike up to 6 metres high in place in September. Last year it was inundated with up to 4.3 metres of floodwater.

"Flood-affected companies and industrial estates are doing what they can to defend themselves better, but of course we can't do it entirely without the government's help," Kobkarn said.

"If the factories and industrial estates are safe from floods but our staff's homes are submerged, they won't be able to come to work anyway. We need the government to support us," she said.

Toshiba had to halt operations at nine of its 10 production plants at Bangkadi and one in Nava Nakorn Pcl NNCL.BK estate in Pathum Thani province in the north of Bangkok. It may take a year for some to be up and running again.

(Additional reporting by Pisit Changplayngam; Editing by Alan Raybould)

• A Permanent Economic Emergency