Renate Künast, parliamentary head of the Green party, told daily Hamburger Abendblatt that drivers should pick cars from the German automobile club's (VCD) list of low-emission vehicles, the top six of which are Japanese.
"As a Green, I want people to buy cars with the lowest CO2 emissions. The VCD list of the 10 most environmentally-friendly car shows a good way forward," she told the paper.
The list is topped by the Toyota Prius Hybrid car, with another Toyota model in second place. Two cars by Honda, a Nissan and a Suzuki occupy the next four places.
Two Daimler "smart" cars come in seventh and eighth and Germany's Volkswagen Polo brings up the rear.
Künast's comments come a day after the German government unveiled an initiative to boost the production of electric cars, aiming to have a million such vehicles zipping around the country by 2020.
They also come in the midst of a campaign for the country's general election on September 27. The opposition Greens are currently earning about 12 percent in polls.
Two years ago, Künast drew fire from Germany's powerful car industry after saying, "If the Germans are too stupid to build modern cars, I must recommend to people that they buy the Toyota Prius."