Toyota Motor Corporation is to boost monthly production of the Prius petrol-electric hybrid sedan from approximately 10,000 units per month to 15,000.

Separately, Toyota Motor Sales USA said it it is negotiating with TMC to significantly increase its North American allocation of the Prius for model-year 2005, to help meet the vehicle's unprecedented demand in the US market.

"When the all-new second-generation Prius was launched in mid-October of last year, we had an annual sales plan of about 36,000 units," said Don Esmond, Toyota Division senior vice president and general manager. "Two months later, in December 2003, we announced a 31% increase in our sales plan to 47,000 units annually, and promised that if we needed more, we would build more.

"Clearly, the extraordinary response to Prius took us by surprise.  With demand far-outstripping supply, customers have been forced to wait many months for delivery. Our announcement to increase production by 50% should prove to our dealers and our customers that we are good on our word."

The additional 5,000 units per month will be built on an existing assembly line at an existing production facility in Japan. The specific location of the plant will be announced later. Production will begin during the first half of 2005.

The newspaper USA Today this week reported that Toyota dealers are no longer taking orders for the Prius because the waiting list is so long.

A recent CBS News report on the model's success said waits of six to eight months were not uncommon.