Aftershocks have rattled south-western Japan after a strong earthquake killed nine people, injured at least 1,000 and cut power and water across the region.

Key points: More than 130 aftershocks in south-western Japan following quake

More than 130 aftershocks in south-western Japan following quake Thousands of households without electricity and water

Thousands of households without electricity and water Factories suspended operations

By Friday afternoon, more than 130 aftershocks had hit the area around the city of Kumamoto in the wake of the magnitude-6.5 earthquake the night before.

Officials said the frequency was tapering off but the risk of further strong aftershocks will remain for about a week.

A earthquake victim rests with a pet dog at an evacuation centre in Mashiki town. ( Reuters: Kyodo )

Although the magnitude of the earthquake was much lower than the magnitude-9 quake on March 11, 2011 — which touched off a tsunami and nuclear meltdowns at Fukushima — the intensity was similar because it struck on land and at a much shallower depth.

"We managed to huddle into a space, that's why we were saved," one man told Japanese broadcaster NHK after he and his family were rescued from their collapsed house two hours after the quake hit.

"We're all safe, that's what counts."

More than 44,000 people initially fled to schools and community centres, some spending the night outside after the earthquake hit.

Roads cracked, houses crumbled, and tiles cascaded from the roof of the 400-year-old Kumamoto Castle in the city's centre.

Among those pulled from the wreckage was an eight-month-old baby girl, wrapped in a blanket and passed hand to hand by firefighters.

Damage to Kumamoto Castle caused by the earthquakes (bottom left of picture) ( Reuters: Kyodo )

Hospitals evacuated, factories suspended

Hospitals had to evacuate patients and several companies, including Honda Motor Corp, Sony Corp and tire maker Bridgestone Corp suspended operations at factories in the area.

More than 3,000 troops, police and firemen were dispatched to the area from around Japan, and Prime Minister Shinzo Abe said more would be sent if needed.

"We will do everything in our power to ensure the safety of local residents," Mr Abe told a parliamentary committee.

Sorry, this video has expired Huge quake hits Japan's Kumamoto

Most of the dead came from Mashiki, a town of around 34,000 people near the epicentre of the quake, where firefighters battled a blaze late on Thursday.

Daylight showed splintered houses under tiled roofs and an apartment building with a pulverised floor, where two people died.

"I want to go home, but we couldn't do anything there," one boy at an evacuation centre told TBS television as he bounced a baby in his arms.

Trains derailed, highways closed

Construction workers restore a damaged road beside a graveyard in the town of Mashiki. ( AFP: Jiji Press )

Service on the Shinkansen superfast train in Kyushu was halted after one train derailed, and highways were closed after some sections collapsed.

About 12,200 households were without electricity on Friday afternoon, according to Kyushu Electric Power Co Inc, while around 58,000 lacked water.

The Nuclear Regulation Authority said there were no irregularities at three nuclear plants on the southern major island of Kyushu and nearby Shikoku.

The 2011 quake temporarily crippled part of Japan's auto supply chain, but some companies have since adjusted the industry's "Just in Time" production philosophy in a bid to limit any repeat of the costly disruption.

Though the intensity of Thursday's quake on the Japanese scale matched that of the March 2011 quake, which left nearly 20,000 dead, the absence of a tsunami helped keep the death toll down.

Map Map showing the epicentre of the earthquake.

Reuters