Dacia management says that car building will be at 80 percent of the level before the shutdown at the factory in Mioveni, some 60 miles (100 kilometers) northwest of the capital Bucharest.
Union leaders said they will organize a protest in the town on Tuesday to demand that jobs in the car industry are protected. The company owned by French Renault SA employs about 14,000 workers.
The company said the economic crisis led to a 50 percent drop in cars sales in Romania in November 2008 compared to the year before. Renault SA has invested euro1 billion ($1.28 billion) in Dacia since buying it in 1998.