Japanese car maker Daihatsu has suspended all its domestic production as the Toyota-owned company faces a massive safety testing scandal.

The firm, which has about 9,000 factory workers in Japan, closed the last of its four domestic plants, a Daihatsu spokesman told AFP on Tuesday.

"Production will be suspended through January. We have not been able to assess as to exactly when our domestic production can resume," the spokesman said.

The move could affect more than 8,000 companies across the country, according to a private research firm.

Last week, the company said it had been manipulating safety tests since at least 1989, affecting 64 models, including some sold under the Toyota brand which also is being suspended.

In April it said it had been falsifying crash test results for four of its models, involving a total of 88,000 vehicles made in Thailand and Malaysia in 2022 and 2023.

In May, it announced it was halting production in Japan of two hybrid vehicle models because of similar "irregularities", including the Toyota Raize SUV, manufactured on behalf of its parent company.

Founded in 1907 to manufacture internal combustion engines, Osaka-based Daihatsu launched its first three-wheeled vehicle in 1931, before being taken over by Toyota in 1967.