Fuel economy figures for more than 600,000 cars sold in Japan were falsified, Mitsubishi Motors Corporation (MMC) executives have admitted.

More than two thirds of the cars, 468,000, were manufactured by MMC and supplied to Nissan Motors Corporation. The issue was uncovered when Nissan queried data supplied by MMC.

The affected cars are four mini-car models, MMC’s eK Wagon and eK Space, and Nissan’s Dayz and Dayz Roox. They have 660cc petrol engines and although they are popular in Japan few have been sold overseas.

In a statement MMC said it had stopped production and sales of the cars and that it would discuss compensation with Nissan.

Its initial investigation had focused on models sold in Japan, but it added: “Taking into account the seriousness of these issues, we will also conduct an investigation into products manufactured for overseas markets.

“In order to conduct an investigation into these issues objectively and thoroughly, we plan to set up a committee consisting of only external experts. We will publish the results of our investigation as soon as it is complete.”