The market for new cars in the European Union shrank considerably last month, a trade group said Wednesday, explaining it as a one-off effect of the introduction of new emissions rules.

About 1.09 million cars were sold in the bloc in September, in a year-on-year reduction of 23.5 per cent, the European Automobile Manufacturers Association (ACEA) said in its monthly bulletin.

"However, this should not come as a surprise," ACEA said.

The association explained that the sales drop followed a year-on-year surge of 31.2 per cent registered in August, when cars not compliant with the new emissions standards were heavily discounted.

The new standards, called the Worldwide Harmonised Light-Duty Vehicles Test Procedure (WLTP), are applicable to cars registered from September 1.

Looking at January-September, the EU car market kept growing, ACEA said, with 11.95 million units sold, up 2.5 per cent from the same period of 2017.

In the EU's biggest markets, demand for new cars rose by 11.7 per cent in Spain, 6.5 per cent in France and 2.4 per cent in Germany, and shrank 2.8 per cent in Italy and 7.5 per cent in Britain.

Volkswagen, the EU market leader, took a 24.2-per-cent share of sales in the first nine months of the year, an improvement from the 23.5-per-cent quota held in January-September 2017.

French groups PSA and Renault remained second and third in the market share ranking, with 16.2 per cent and 10.7 per cent, followed by Fiat-Chrysler with 6.8 per cent and Ford with 6.4 per cent.