Mrs Schmidt could be summoned before the budget committee
The German health minister, Ulla Schmidt, has been criticised after her official car was stolen in Spain, where she was using it during her vacation.
The 90,000 euro (£78,000) Mercedes S-class was stolen in Alicante.
Mrs Schmidt flew there at her own expense. Her chauffeur drove 2,400km (1,500 miles) to meet her so she could carry out some official business.
But opposition politicians want to know why she needed her car in Spain, when embassy vehicles are available.
A German taxpayers group also weighed in, telling the Bild am Sonntag newspaper: "Taxpayers' money should not be wasted on the comfort of a minister".
Officials at her ministry said Mrs Schmidt, like all cabinet members, has a car at her disposal at all times for official and private use.
They said she was meeting on Monday with Germans living in Spain, and that the minister would reimburse the cost of private use, in accordance with the rules.
Thieves stole the keys from the chauffeur's accommodation near Alicante, a popular retirement and holiday destination for Germans on Spain's Costa Blanca.