TOKYO (Reuters) - Domestic vehicle sales at Mitsubishi Motors Corp <7211.T> roughly halved in May for the second straight month as demand continued to fall after the Japanese automaker admitted to overstating the mileage of four mini vehicles it produced.

Sales at Nissan Motor Co Ltd <7201.T> also suffered, led by mini vehicles, or "kei" cars, as the company markets two of the affected models supplied by Mitsubishi Motors.

Sales of the four models have been stopped since Mitsubishi in April admitted to the falsification. The company has said it plans to resume production early next month, after Japan's transport ministry said the classification of the vehicles had not been affected by the issue.

Mitsubishi said overall domestic sales for last month fell 51.6 percent from a year earlier, led by a 75.0 percent tumble in sales of mini vehicles. Domestic production slumped 39.8 percent on the year.

Domestic sales at Nissan fell 26.2 percent in May from last year, led by a 76.8 percent fall in mini vehicles.

Suzuki Motor Corp <7269.T>, which last month admitted to using incorrect data to calculate mileage for many of its mini vehicles, reported a fall of 6.6 percent in overall domestic sales, after mini vehicle sales fell 15.4 percent.

(Reporting by Naomi Tajitsu; Editing by Christopher Cushing)