Report the Exercise of STEC-W No.16 and STEC-W2 No.7

Ref: ST/010/2007/0002 January 4th, 2007 Re: Report on the Exercise of Warrants (STEC-W No.16/2006, STEC-W2 No.7/2006) To: The President The Stock Exchange of Thailand Sino-Thai Engineering & Construction Public Company Limited would like to report the exercise of STEC-W No.16 and STEC-W2 No.7 on January 3rd, 2007 as per following details: - Exercising ratio: 1 unit of warrant per 1 ordinary share - Exercising price of STEC-W : Baht 1 per share - Exercising price of STEC-W2 : Baht 8.50 per share - Ordinary shares reserved to support the exercise of STEC-W: 1,806,550 shares, and STEC-W2: 163,548,461 shares - None of both STEC-W and STEC-W2 holders exercise the warrants. - Total remaining warrants listed in the Stock Exchange of Thailand of STEC-W:1,806,550 units, and STEC-W2:163,548,461 units Please be informed accordingly. Yours sincerely, Mr. Woraphant Chontong SEVP. Financial and Administration Division