Volkswagen has admitted rigging emissions tests in Europe in the same way it falsified results in the US, Germany's transport minister has said.
The company has had to recall more than half a million of its vehicles in the United States after admitted it deceived US regulators in exhaust emissions tests, by installing a device to give readings below those seen in normal driving conditions.
The company admitted using the same fake emissions test in Europe as it used in the US, Germany's transport minister has suggested.
Alexander Dobrindt said it was not known how many of the 11 million vehicles affected were in Europe.
He also said other manufacturers' vehicles would be checked.
The scandal began unfolding when the German car giant said it had used software in the US to provide false emission test results.
Mr Dobrindt said he had been told vehicles with 1.6 and 2.0 litre diesel engines are "affected by the manipulations that are being talked about".
The company's Jetta, Beetle, Golf and Audi A3 models in the US from 2009 to 2015, and the Passat from 2014-15, were fitted with the devices which produced doctored results.
Its New Zealand general manager Tom Ruddenklau said he had no idea when he would know if Volkswagen New Zealand's cars were affected.
"I've been flat out talking directly [to customers]. In some ways it's been a bit frustrating because I can't actually them too much and that we've been taking it seriously - because we are.
"Quite rightly they're raising all sorts of questions interestingly enough not all of them have not got much to do with emissions. Their trust in the brand is being questioned."
Volkswagen could be facing fines in the US of up to $US18 billion, and chief executive Martin Winterkorn has resigned over the recall.
The value of Volkswagen shrunk by about 30 percent since the scandal was revealed.
Separately, BMW shares dropped by 10 percent on reports the false tests had been used by other carmakers.
A serious breach of trust
A crisis management expert says Volkswagen's diesel bungle highlights that deception is never a good idea.
Victoria University associate professor Dan Laufer, said an investigation should be carried out by a third party.
"It is very important for Volkswagen to find credible parties and credible individuals that will be part of this sort of investigation," he said.
He said that deception is not good.
"Corporate misdeeds and deception is never a good idea and I think that a lot will come out of the investigation - how it happened," he said.