Honda said Wednesday it had temporarily halted production at a plant in Japan after it suffered a cyberattack from the same ransomware that struck hundreds of thousands of computers worldwide last month.

The Japanese automaker said it had shut its plant in Sayama, near Tokyo, on Monday after discovering its computer system was infected with the so-called WannaCry virus.

The virus encrypts computer files, making them inaccessible until users pay a ransom.

"The malware affected the production of about 1,000 cars," a Honda spokeswoman told AFP, adding that production restarted on Tuesday.

"There is a possibility that our overseas facilities were also infected... We're now investigating that," she added.

Honda's plant produces a number of models including the Accord sedan and Odyssey Minivan.

The unprecedented global cyberattacks, which started in mid May, struck banks, hospitals and government agencies in more than 150 countries, exploiting known vulnerabilities in old Microsoft computer operating systems.

In May, French auto giant Renault was hit, forcing it to halt production at sites in France, Slovenia and Romania as part of measures to stop the spread of the virus.

Nissan's British unit in Sunderland was also hit in the attack.

In Japan, 2,000 computers at 600 companies and organisations had been affected by the May virus, according to media reports.

Japanese conglomerate Hitachi was also affected, saying its computer networks were "unstable", crippling its email systems.

Authorities across the world have issued public alerts warning computer users to beware of suspicious emails and beef up their computer security measures.