Nova Corp. teachers and other employees in Tokyo criticized the company Tuesday, saying the troubled chain of foreign-language schools must improve its business not just so it becomes more honest with customers but also for the sake of its workers.

At a news conference, Nova union members also demanded that the firm provide better working conditions for the Osaka-based chain's roughly 5,000 teachers at its branches nationwide. Although teaching English is Nova's mainstay, it also offers lessons in other foreign languages.

The rank and file said Nova must improve its thorny relations with its union if the chain hopes to survive the current crisis, in which it was slapped with a six-month ban on offering new long-term student contracts.