TOKYO: Subaru Corp on Wednesday said it was investigating whether its inspectors may have falsified data on vehicle mileage readings during final inspections conducted on cars sold in Japan.

The Japanese automaker in October revealed that uncertified staff had been carrying out tests on new cars sold on the domestic market for decades, and on Tuesday vowed to improve oversight.

On Wednesday it said in a statement that some inspectors had told external investigators that mileage data had also been altered on some models during the final checking process.

It added that it had not confirmed that any such fabrications had taken place.

Subaru shares fell as much as 8.5% on Wednesday and were the most heavily traded stock by turnover on the Tokyo Stock Exchange.