Fast food giant McDonald's Japan says many of its restaurants have suspended operations due to an unidentified system failure.

The chain operator says the trouble occurred on Friday afternoon when cash registers became unusable.

Staff at some restaurants took orders from customers with pen and paper, while others decided to close until the technical issue is resolved.

One outlet in Tokyo's Shibuya Ward initially resorted to taking orders manually, but stopped operations after its staff became overwhelmed. A "temporarily closed" notice has been placed at the entrance.

A female customer says it's a pity she cannot order food and drink at the outlet, which she often visits.

McDonald's Japan says it is working to identify the cause of the trouble and how many outlets are affected.

The company apologizes for causing inconvenience to customers, and says it will let them know when temporarily closed outlets are ready to reopen.

Major media organizations outside Japan are reporting that system failures have also occurred at McDonald's restaurants in Australia, South Korea, New Zealand and elsewhere.

NHK contacted overseas restaurants and learned that those in Thailand, South Korea and Hong Kong were hit by technical issues but services are gradually resuming.