Japan's Self-Defense Forces are on alert as North Korea appears poised to fire a ballistic missile in what it calls a "satellite" launch.

The Japanese government says North Korea has notified it that the launch is planned for a period between this Wednesday and June 11.

Destroyers equipped with the Aegis missile-tracking system, which has advanced radar and interceptor missiles, are on standby around the clock in the East China Sea.

Land-based PAC-3 interceptor systems have been deployed in Naha City, on the islands of Miyako, Ishigaki and Yonaguni in Okinawa Prefecture, and on the premises of the Defense Ministry in Tokyo.

The Ground Self-Defense Force has sent units to Okinawa that are tasked with removing hazardous materials and rescuing injured people in the event of a ballistic missile falling in the area.

When Pyongyang launched what were believed to be ballistic missiles in 2012 and 2016 following notifications of satellite launches, the SDF deployed PAC-3 systems at similar locations but did not fire any interceptor missiles.