A Japanese official has been left red faced when he mistakenly announced the launch of a North Korean missile instead of sending an alert about a strong earthquake.

An official at the western Osaka aviation bureau emailed 87 airport offices to say a North Korean missile had been launched.

The official was trying to send a message to check on possible airport damage immediately after the 6.3 magnitude earthquake struck near the southwestern city of Kobe last night. 

But instead the official dispatched a pre-prepared alert ready to go in the event of a North Korean missile launch.

The incorrect message was retracted six minutes later and at least one domestic flight was delayed due to the mistake.