Nippon Yusen K.K., the world's largest operator of car transport ships, may double the number of carriers it retires as Toyota Motor Corp., Honda Motor Co. and Nissan Motor Co. slash production.

The carrier may scrap and park as many as 20 car carriers, on top of the 20 it is already planning to scrap by March 2010, Mikitoshi Kai, head of investor relations at the shipping line, said Friday.

"Every day we are asking auto manufacturers about their export plans for next year, but we have not yet received any figure," he said.

Nippon Yusen predicts car exports will slump more than a third this quarter. Tighter lending and rising unemployment in the U.S. led to a 37 percent decline in vehicle sales last month. Toyota will slash domestic production 54 percent this quarter as demand plunges, and Nissan aims to cut 20,000 jobs as it trims output worldwide.

"Exports are doing very badly," said Edwin Merner, president of Atlantis Investment Research Corp. in Tokyo. "The carmakers have basically told the shippers, we don't need you anymore."