The 57-metre (190-feet) H-2A rocket, carrying two satellites - a data relay satellite and an unmanned space experiment recovery system.

It blasted off from the Tanegashima spaceport, about 1,000 kilometres (625 miles) south-west of Tokyo at 1720 local time (0820 GMT).

Within 30 minutes of blast off both of the satellites were successfully deployed, officials said.

Japan's last H-2A launch, in February, failed to put a test satellite into orbit.

High ambitions

"Today's launch, if successful, marks a major step towards commercialisation of Japan's satellite launch business," said an official from Japan's National Space Development Agency (Nasda).

But Japan is yet to find a customer for the programme, which has been criticised for its high cost and a series of launch failures.

The commercial satellite launch market is dominated by the United States and Europe.

Nasda was set up in 1969 and launched Japan's first, totally self-developed rocket, the H-2, in 1994.