Martin Winterkorn, President and CEO of Porsche Automobil Holding SE poses next to a Porsche Cayenne Diesel before the annual shareholders meeting of Porsche in Stuttgart June 17, 2011. REUTERS/Michaela Rehle

BERLIN (Reuters) - The German Transport Ministry has ordered the KBA watchdog agency to examine the emissions of sports car maker Porsche PSHG_p.DE, a unit of Volkswagen VOWG_p.DE, a ministry spokesman said on Monday following a critical media report.

German newsmagazine Der Spiegel reported on Friday that diesel models of Porsche’s Cayenne V6 TDI, an SUV model, had much higher emissions than legally allowed.

The company said it did not understand the test results, and noted that emissions depend on conditions such as engine load, speed and temperature.