Andor, a Hungarian economist and leading light of the country's Socialist Party, told Welt newspaper that there was "no other country in the Eurozone where there is such a big difference between the contractually agreed working week and the actual working week as Germany.”
The average working week specified in German countracts is around 37.7 hours, European studies found.
But the average week worked in practice is at 40.5 hours.
A study published last week by the Institute for Labour Market and Job Research (IAB) found that only half of German overtime hours were paid.
People worked an average of 11.9 hours' overtime in the second quarter of 2014 and were only paid for five.
Andor suggested that the news simply made up part of Germany's national character.
“In the end, what's important is that the country is competitive and that the provisions of the EU Working Time Directive are stuck to – that's generally the case in Germany,” he said.
Under Germany's Working Time Statute (AZO), normal working time should not exceed eight hours a day or 48 hours a week, including Saturday.
Workers are normally compensated for overtime by being given hours back rather than through pay.