The US carmaker Chrysler has announced plans to close its 30 manufacturing plants for a month starting on Friday, as it seeks to counter the most severe downturn in US car sales in more than two decades.

Workers at Chrysler's Warren Truck Assembly facility in the Detroit area expressed disappointment over the shutdown.

"Gets you real depressed. The morale in the plant is not too good right now."

"It's not good. My thoughts are real bad. I don't want to be out of work. It's hard to pay your bills when you're not working."

In a statement, the company blamed tighter credit markets for keeping would-be buyers away from its showrooms, as its sales in November has slid over 47 percent.

One Detroit area Auto dealer said the announcement was no surprise, and perhaps even a wise decision.

"Dealers have to pay interest on the cars that are sitting here and all of that, so I think it's a wise decision. I mean, it's a very painful decision for the people that work in those plants and now don't have a job for the holidays and less money coming in in any event."

With the US sales slump expected to continue into January, traditionally one of the slowest sales months of the year, the company has little revenue coming in and must pay suppliers seven billion US dollars every 45 days.

Chrysler's large rivals, General Motors and Ford have also announced extensions of their holiday shutdowns.