The survey, conducted by the Sasin Graduate Institute of Business Administration at Chulalongkorn University from February to March, covered 514 companies. Slightly more than 20 per cent were foreign firms.

About 43 per cent of all respondents said they would maintain their planned investment this year, while 35 per cent said they would continue to expand their investments in Thailand.

Only 4 per cent of respondents said they would reduce the size of their businesses or move to invest in other countries.

Most respondents were still optimistic about total sales - both domestically and internationally - in the second half of this year, believing they would be higher than in the first six months. The manufacturing production index in the second half was also expected to be higher than in the first half.

Many firms said that investing in Thailand was attractive, mainly due to good infrastructure, logistics and protection of intellectual property rights, compared to India, China, Vietnam and Malaysia.

However, they commented that the country's investment sentiment was cloudy as a result of the fluctuation of oil prices, foreign-exchange rates and financial-control measures.

"Foreign operators would rather focus on the country's infrastructure, market potential and logistics than the current political chaos," secretary-general Satit Charnjavanakul told the press in a meeting on Friday.

He said BoI officials would stage a road show in Australia next week to attract operators in the automotive and auto-parts industries to invest here.

The BoI reported that the total value of net applications for taxes and privileges in the first five months was Bt200 billion, an increase of 73.6 per cent from the same period last year.