Porsche Cayenne Diesel
Porsche's Cayenne model: The German automaker could ditch diesel engines soon, according to its CEO. Porsche

Porsche will decide at the end of the decade whether its latest generation of diesel engines will be its last, according to the luxury automaker's boss.

"We have not made a decision on it. Of course we are looking into this issue. For the generations that will follow there are different scenarios," Chief executive officer Oliver Blume told Reuters.

One scenario has Porsche backing out of making diesel cars altogether. Diesel cars currently account for about 15% of its global sales.

Blume is the first German auto industry boss to express doubts about diesel cars. He added that Porsche would offer a mix of "combustion engines, plug-in hybrid vehicles and purely battery-powered cars" over the next 10 to 15 years.

The automaker is spending €1b (£890m) to overhaul its main Stuttgart plant and build its first battery-only model - the four-door Mission E saloon which is due on the market in 2019.

Battery-only vehicles could account for a quarter of Porsche's sales by 2025, give or take 5 to 10% points, Blume said, contradicting reports that said up to half of its output by 2023-24 could be electric.

Blume's comments follow parent company Volkswagen's emissions cheating scandal in 2015 resulting from revelations in the US about the automaker having installed software aimed at defeating emissions tests. The legal fallout from the episode continues.

The scandal has cast a shadow over Porsche, which first introduced diesel in its Cayenne sports utility vehicle (SUV) in 2009, is considering its options.

German prosecutors are currently investigating Porsche staff to see whether they were involved in designing the maligned software and whether the Cayenne was fitted with such a device.