Japan's four biggest truck makers are considering skipping the 2009 Tokyo Motor Show this fall, industry sources said Thursday.

Isuzu Motors Ltd., Hino Motors Ltd., Nissan Diesel Motor Co. and Mitsubishi Fuso Truck and Bus Corp. are trying to reduce expenses and distance themselves from the show as sales continue to plunge amid the global economic slump, the sources said.

The U.S. Big Three — General Motors Corp., Ford Motor Co. and Chrysler LLC — have already decided not to go to the show, along with Sweden's Volvo, a Ford subsidiary.

In contrast, Porsche AG and Renault SA plan to attend, the sources said.

Leading automakers from Japan and other countries will display hybrid cars, vehicles boasting new fuel-saving technologies, and other vehicles fitted with a range of safety and less environmentally destructive components, they said.

Japan Automobile Manufacturers Association Chairman Satoshi Aoki, who doubles as chairman of Honda Motor Co., suggested at a news conference that the chief organizer may have to scale the show down.

"The economic environment and business environment surrounding the auto industry are going through a range of changes, so we are considering what the show should be like," Aoki said.