Gerald Klug (SPÖ) faces questions from the opposition in parliament on Thursday and further allegations of misuse of funds. There are calls from within the conservative People’s Party (ÖVP) for him to step down as minister and for there to be a cabinet reshuffle.
The chauffeur travelled from Vienna to Zurich to pick Klug up and then onto France, and back to Austria.
"The minister must calculate the costs for the chauffeur and pay the Republic back! This is simply outrageous to commandeer an army driver and luxury BMW for a private trip," Green security spokesman Peter Pilz said.
"The minister has made cuts to the Eurofighter pilot programme, but can still afford a chauffeur for a private luxury trip," he added.
In a statement the defence ministry said: "We must stress that the Chancellor's office determined that the use of the company car was legal." It did not say whether the minister would be willing to pay back some of the costs of the trip.
Previously Klug has said that he pays a monthly fee of around €600 for the car and is therefore allowed to use it for both business and personal trips.
According to a report in the Kronen Zeitung, high ranking officers within the army are now asking who Klug was visiting in France, and if he ordered the chauffeur to drive him.