GERMAN authorities have announced the recall of 22,000 Porsche cars and a sales ban to remove what they consider is a "defeat device" that manipulates emissions levels.

Germany's motor transport authority, KBA (Kraftfahrt-Bundesamt) said there was an immediate ban on the registration of one of Porsche's most popular models, the Cayenne Diesel after official tests discovered suspect software that manipulates carbon-dioxide emissions.

Porsche said it was taking “full responsibility” to customers and is cooperating closely with authorities.

Last month Germany's transport ministry said it was to test the luxury Porsche Cayenne 3-litre TDI following reports that it could be in breach of diesel emissions limits.

Porsche's sister company Volkswagen admitted in 2015 that some of its diesel cars were fitted with a "defeat device" to cheat on emissions tests and change performance.

Authorities will order an obligatory recall as in previous such cases, he added, saying 7,500 of the vehicles have been registered in Germany and 22,000 across Europe.

It is not clear how many more are with dealers or in production.

German Transport Minister Alexander Dobrindt  said the finding resulted from tests carried out by German authorities.

Allegations first surfaced in a German magazine which found the car’s emissions were higher than allowed.

Porsche at the time said the test was “implausible” and that its vehicles met emissions requirements.

But Mr Dobrindt said  “a so-called warm-up strategy” is triggered when cars are being tested that is not activated during normal driving. The emissions of nitrogen oxide, a pollutant that is harmful to health, are much higher when the car is on the road, he said.

Talks with the manufacturer also raised suspicions there may be similar software in a Volkswagen Touareg 3-litre diesel model, but authorities still have to carry out tests on it, he added.

Speaking about the Cayenne, he said: "There is no explanation as to why this software is in this car," arguing that the vehicle has a modern emissions system and is technically able to comply with emissions limits. That should mean Porsche can quickly produce modified software that complies with the law, he added.

Porsche released the following statement: "Porsche has detected irregularities in the engine control software during internal investigations and has actively pointed this out to the Kraftfahrtbundesamt (KBA), German Federal Motor Transport Authority. The irregularities are not related to the transmission control software. Corrections by means of a software update within the scope of a recall were agreed with the authority.

"Regardless of the recall, Porsche continues to carry out internal audits on its vehicles and derive optimizations from them. Furthermore, the company is still in close contact with the authorities, in particular the German Federal Motor Transport Authority, on all current matters."