Toyota Motor Corp. said Thursday it has discovered inappropriate spending of about ¥300 million by former employees who were engaged in the development of new concept vehicles.

Toyota said disciplinary measures have been taken and it is considering whether to file a criminal complaint or demand damages over the case, which came to light in May.

The former employees are believed to have charged the automaker, or had its contractors pay, for travel and entertainment expenses not related to their business activities over three years from fiscal 2009, according to Toyota.

Toyota said it will do its utmost to prevent a recurrence of such an incident.