The company's 3,000-strong Halewood plant workforce was on standdown last week, and just three production days are on the rota for next week.
Jaguar could not comment on Halewood's production in the following weeks because the May rota had not yet been drawn up. It said the scaledown was a "sensible thing to do" after worldwide sales fell by 29% in the three months to the end of March.
The manufacturer has already dropped plans to make 200,000 cars a year, and is ending production at its Browns Lane plant in Coventry later this year.
Yesterday, Ford reported a drop in first quarter profits to $1.2bn (£630m).
A spokesman for Jaguar said: "We have to deliver a strategy of less volume and more revenue per vehicle. We know that we have cars in the pipeline and with the dealers. We don't want to flood the market."
He said that there were no concerns about potential job losses and pointed out that from next year Land Rover's new Freelander model would be made at the plant.
Unions were relaxed about the shutdown. A spokesman for Amicus was confident the problems would end once production at Browns Lane ceases in July.
Jaguar's sales fell 21% in the first three months of 2005, as a result of refocusing its car range in the US towards top-of-the-range models, the company said.
Production line staff at Halewood will work on Tuesday, Wednesday and Thursday next week, Jaguar said.
The end of car production in Coventry will result in 1,150 job losses, although the Browns Lane site will remain Jaguar's headquarters.