Chris Grayling made the remarks to the Daily Mail, which said the government was considering a scrappage scheme for older diesel cars.
He told the Mail: “People should take a long, hard think about what they need, about where they’re going to be driving, and should make best endeavours to buy the least polluting vehicle they can.
“I don’t think diesel is going to disappear but someone who is buying a car to drive around a busy city may think about buying a low-emission vehicle rather than a diesel.”
In November the High Court ordered ministers to cut NOx levels in the “shortest possible time”. The minister said this ruling created a legal duty to act, adding: “It is inevitable over the coming years we’re going to have to really migrate our car fleet, and our vehicle fleet more generally, to cleaner technology.”
The Mail also reported that Department for Transport sources stressed that Grayling was not telling people to stop buying diesel cars, but urging them to consider whether a less polluting vehicle might suit their needs.
A source pointed out that ministers have already announced incentives for electric car purchases and are investing heavily in a nationwide charging network.
Grayling said previous governments had encouraged diesel cars for “understandable reasons”, but added: “We have now learned much more about the health impact of NOx emissions and it’s clearly not an issue we can now ignore.”