Japan's government said it will launch a back-up spy satellite on Sunday, after canceling an earlier lift-off due to bad weather.

Tokyo put spy satellites into operation in the early 2000s after its elusive neighbor North Korea fired a mid-range ballistic missile over the Japanese mainland and into the western Pacific in 1998.

Four Japanese intelligence satellites are currently in orbit -- two optical satellites and two radar satellites.

The backup satellite will supplement the two radar satellites, a government official said Friday.

The Japan Aerospace Exploration Agency (JAXA) and Mitsubishi Heavy Industries delayed the planned Thursday launch of the H-2A rocket from the Tanegashima Space Center in southwestern Japan.

They said it was due to the possible presence of lightning during lift-off.

The new launch is set for 10:21 am (0121 GMT) on Sunday, JAXA and Mitsubishi Heavy said, adding that it could be postponed again "depending on weather conditions".