The Fair Trade Commission on Wednesday ordered 113 construction companies to stop rigging bids on public works for the Niigata Municipal Government.

The FTC said that in terms of value, roughly a third of the bids for the city's civil engineering works and more than 60 percent of building construction works were rigged between April 1999 and last September.

FTC officials told a news conference in Tokyo that the commission suspects that the companies involved also rigged bids before April 1999, but could not find sufficient evidence.