Toyota Motor Corp will continue to sell the current, six-year-old Prius alongside the upcoming new version, at least in Japan, its president said on Thursday.

They will have different engine sizes -- 1.5 liters and 1.8 liters -- and we figure there will be demand for the two to co-exist, President Katsuaki Watanabe told reporters at the unveiling of the new Crown Majesta sedan.

He declined to say whether Toyota will do the same outside Japan. Executives in the United States and Europe have said the current model will be discontinued when the new version is rolled out. The new Prius will be launched in May in Japan.