The Japanese earthquake means lost hours for workers at the Honda plant in Alliston.
A shortage in specialized parts coming from Japan means the plant is cutting production to 300 cars a week, down from 700.
The overtime shift slated for Saturday has also been cut.
Honda's workers were told last Friday that normal production would continue until April first.
About 95 per cent of parts needed in Alliston are made in North America, but work has been interrupted at Japan's plants that provide specialized parts.
Production in Japan was expected to start up again this week.
Honda employs 4,200 people in Alliston, who build Civics, and several models of Acura.