Local builders are coming under increasing pressure as they undergo investigation for suspected bid-rigging amid difficult market conditions, industry sources said Wednesday.

Insiders said the Fair Trade Commission is examining all large-scale public construction projects undertaken during the previous Lee Myung-bak administration.

The FTC has not confirmed the investigations, but industry sources said at least seven or eight builders are being probed over work related to railway lines in Busan and Daegu and highways.

Authorities have already slapped fines exceeding 111.5 billion won ($105 million) on Hyundai E&C, GS E&C and SK Engineering and Construction, which were involved in the so-called four rivers project, and 132.2 billion won in fines on 21 builders that built a subway line in Incheon.

Some say the probes come at a rough time for the industry as a whole, and is causing some to stay clear of public work projects altogether. They expressed concerns that the FTC fines may reach as high as 1 trillion won. (Yonhap News)