The Japanese government's top spokesperson says the country is taking steps to prepare for a possible launch of a North Korean military spy satellite.

Chief Cabinet Secretary Hayashi Yoshimasa spoke to reporters on Friday, following a media report from South Korea that Pyongyang is preparing to launch such a satellite.

A report by Yonhap News Agency on Thursday quoted South Korean military sources as saying a covering was set up recently at a satellite launching station in a northwestern region of North Korea.

Pyongyang said it successfully launched its first spy satellite in November.

Hayashi said North Korea has announced it will launch an additional three spy satellites this year. He expressed the view that the North may conduct a launch to send a satellite into space.

He said the Japanese government will stay on alert and do its utmost to monitor moves by North Korea, while gathering and analyzing intelligence in close cooperation with the United States and South Korea.

Hayashi also said Japanese Self-Defense Force Aegis destroyers, as well as the land-based PAC-3 interceptor systems in Okinawa Prefecture, are ready to respond if a spy satellite launched by the North falls onto Japanese territory.