A powerful magnitude-6.5 earthquake has hit Japan’s south-western island of Kyushu, collapsing homes, sparking fires, leaving at least nine people dead and injuring hundreds, government officials say, as the scramble continues to rescue people feared trapped in the rubble.

At least 12 people were injured and 19 houses collapsed in Kumamoto prefecture on Kyushu, Chief Cabinet Secretary Yoshihide Suga, the government’s top spokesman, announced, adding that 350 military personnel had been dispatched for rescue work.

At least nine people were confirmed dead, Kumamoto disaster management official Yutaka Nasu said.

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Kumamoto prefectural official Shunsuke Sakuragi said: “We also received information indicating a few people were under collapsed houses.”

The quake struck at 10:26pm (AEST) in Kumamoto, central Kyushu, at a relatively shallow depth of 10km, the Japan Meteorological Agency said, adding there was no danger of a tsunami.

Hours later a another powerful quake measuring magnitude-6.4 hit the same region just after 1am (AEST) on Friday, according to the Japan Meteorological Agency.

The US Geological Survey measured the first quake at 6.2, and put the second quake at 5.4 — another smaller aftershock followed.

Aftershocks were likely to continue for about a week, it said.

apanese media reported that some 16,000 households in the area were without electricity and 38,000 homes had no gas supplies in Kumamoto.

Prime Minister Shinzo Abe convened an emergency response meeting of emergency officials at his office to plot a response.

“We intend to do the utmost to grasp the situation,” Mr Abe said.

“I’m now planning to hear what we have gathered on the situation.”

Jiji media reported that bullet train services were halted on the island, while NHK said one of the trains had derailed though it was not carrying passengers at the time.

Evacuees gather in front of the town office building after escaping homes after the earthquake struck. Photo: ABC

Houses collapsed, nuclear facilities checked

NHK reported that some buildings had collapsed in the town of Mashiki in Kumamoto with people possibly trapped underneath.

It showed what appeared to be a house in flames as firefighters attempted to douse it with water — it reported a total of three fires sparked by the quakes.

Meanwhile, Japan’s two sole operating nuclear reactors, located on Kyushu, were functioning normally, an official at the Sendai plant operated by Kyushu Electric Power said, though he said technicians were checking for damage.

“We are doing our best for emergency disaster measures by prioritising efforts to save and rescue victims,” Mr Suga said.

“I ask people in the disaster zone to act calmly and help each other.”

Japan sits at the junction of four tectonic plates and experiences around 20 per cent of the world’s most powerful earthquakes.

But rigid building codes and strict enforcement mean even powerful tremors frequently do little damage.

A massive undersea quake that hit on March 11, 2011, sent a tsunami barrelling into Japan’s north-east coast, leaving about 18,500 people dead or missing, and sending several reactors into meltdown at the Fukushima nuclear plant in the worst atomic accident in a generation.

A collapsed house is seen after an earthquake in Kumamoto. Photo: ABC