Japan may face a shortfall in supply of replacement air bags as automakers recall 9.8 million vehicles in the country to swap out potentially defective devices made by Takata Corp., according to the transport ministry.

Toyota Motor Corp., Honda Motor Co. and Nissan Motor Co. are among Japanese carmakers that have stepped up precautionary recalls in their home market after widening their safety campaigns in the U.S.

The preventive measures added about 7.3 million vehicles to the repair list. Automakers are first fixing older vehicles and those that are believed to have higher risk of rupture, according to Masato Sahashi, director of the recall enforcement office at Japan's transport ministry.