The cabinet on Tuesday approved the qualifications of six investment groups to bid for water management and flood prevention projects.
They are K-Water from South Korea, the ITD-Powerchina Joint Venture, Summit SUT Joint Venture, Team Thailand Joint Venture, Thai-Japanese Joint Venture and Loxley Consortium.
TKC Global Consortium, another contender from South Korea, is out of the race. China's CAMC Engineering Co had earlier advised the government of its intention to withdraw from the bidding.
TKC was not qualified because some partners had left the group and CAMC was not approved by the Chinese embassy in Thailand, Deputy Prime Minister Plodprasop Suraswadi said.
He said the approval was not favouring foreign firms competing to win the 350 billion baht in projects, as 31 firms were participating in all six groups, accounting for 65% of total companies.
"The firms that will drive the projects are Thais, not foreigners," said Mr Plodprasop, who chairs the Water and Flood Management Commission.
The six qualified candidates will be allowed three months to work on the design of the projects and enter the bidding contest with detailed plans.
The projects comprise six modules involving Chao Phraya River basin projects worth 300 billion baht. The remaining four modules involve other river basins and are worth 40 billion baht. The other 10 billion baht has been earmarked for infrastructure projects during 2012-2013.
The government allows only three groups to bid for each module.