Japan launched a cargo-carrying rocket Sunday loaded with supplies for the crew of the International Space Station, along with a small robot meant as a companion for one of the country's astronauts.

The H-2B rocket blasted off from the southern island of Tanegashima at 04:48 am local time (1948 GMT Saturday), images broadcast by the Japan Aerospace Exploration Agency (JAXA) showed.

"The HTV4 module has separated from the rocket as scheduled and continues its journey to the ISS," a JAXA spokesman said during the broadcast streamed over the Internet.

"Information on its progress will be given later, as and when," he added of the module which is due to dock at the station on August 9.

The unmanned rocket carried a cargo transporter filled with drinking water, food, clothing and work supplies for the six permanent ISS crew.

The annual mission, which has previously been completed by countries including the United States and Russia, will also pick up waste from the space centre.

"The H-2A and H-2B rockets have been successfully launched total 20 times in a row," said Yoichi Kujirai, chief of the aerospace division at Mitsubishi Heavy Industries, which carried out the project.

"We would like to sell this technology to Asia and the Middle East," he said, as quoted by Jiji Press.

A small talking robot accompanied Sunday's mission. The android is designed to act as a chatting companion for astronaut Koichi Wakata, who is set to arrive at the space station later this year.

Standing at just 34 centimetres (13.4 inches) tall and weighing about one kilogram (2.2 pounds), Kirobo is programmed to communicate in Japanese and keep records of its conversations with Wakata, who is the first Japanese astronaut to command the ISS.

The robot's creator Tomotaka Takahashi and his team posted photos taken near the launch pad on Twitter.

"The launch was so beautiful and breath-taking," they said in a tweet. "Thank you everyone for watching our project so warmly."

The black-and-white humanoid robot, wearing bright red boots, displayed its communication skills in June: "This may look a small step, but it will be a big stride as a robot," Kirobo told reporters.

"Kirobo will remember Mr Wakata's face so it can recognise him when they reunite up in space," Takahashi had told AFP.

"He will be the first robot to visit the space station."

The robot, which has a wide range of physical motion, will also play a role in some missions, relaying messages from the control room to the astronaut.

Sending the android to space is part of a study aimed at seeing how a non-human companion can provide emotional support for people isolated over long periods.

Back on earth, twin robot Mirata will be on the lookout for any problems encountered by its electronic counterpart, which was inspired by the legendary animation character Astro Boy.

In January, Japan launched two satellites from Tanegashima to strengthen its surveillance capabilities, including keeping a close eye on North Korea after it vowed to launch another nuclear test.

One of them was a radar-equipped unit to complete a system of surveillance satellites that would allow Tokyo to monitor any place in the world at least once a day.

The other was a demonstration satellite to collect data for research and development.