General Motors Co., the largest U.S. automaker, will raise prices by an average of US$123, or 0.4 per cent, per vehicle because of higher commodity costs.

The price increases will be on most models in the U.S. and will be effective May 2, Tom Henderson, a spokesman for Detroit-based GM, said Monday in a telephone interview. The move isn't related to the Japan earthquake, he said.

GM is following Toyota Motor Corp. and Ford Motor Co. in boosting prices. Ford said April 4 it would raise prices by $117, or 0.4 per cent.

Toyota's increase on most models averaged 1.7 per cent, the automaker said March 31.