A giant sinkhole in the heart of a busy Japanese city has sucked in traffic lights and is threatening to collapse surrounding buildings.

The gaping chasm, which is around 30 metres wide, has appeared outside Hakata Station in the city of Fukuoka, on southern Kyushu island.

TV footage showed two separate holes steadily expanding across the five-lane road shortly after 5am local time.

A young man, who saw the sinkhole expand, told public broadcaster NHK: “It was a bit dark outside, and my first impression was, ‘Is the road really falling?’

“When I saw it, two holes were already there, and they continued to grow bigger.

“I got scared the most when a traffic light fell at an intersection close to where I was standing. I felt, ‘I have to get out of here’.”

By afternoon the hole was around 15 metres deep and was filling with water from broken pipes.

Police, who cordoned off the area and evacuated buildings, said there were no reports of any injuries.

Fukuoka’s mayor Soichiro Takashima and transport bureau said ongoing extension work to a nearby subway line might have triggered the crater.

Mr Takashima told a press conference: “We believe the subway construction had some impact.

“A thorough investigation will be carried out.”

The city’s railway station is a major intersection, including for the high-speed bullet trains that criss-cross the country.

At least 170 households reportedly lost power.

Sinkholes around the world Show all 9 1 /9 Sinkholes around the world Sinkholes around the world Dunedin, Florida The rear portion of a residential home is consumed by a sink-hole November 14, 2013. According to reports, the large sink-hole began to form between two houses the morning of November 14, and grew to size of about 30 feet wide by 30 feet deep Getty Images Sinkholes around the world Clermont, Florida A building sits partially collapsed over a sink-hole at Summer Bay Resort near Disney World on August 12, 2013. The 40 to 60 foot sink-hole opened up under the resort building reportedly begining late August 11 into early August 12. There were no injuries or deaths reported Gerardo Mora/Getty Images Sinkholes around the world Shenzhen, China Rescuers prepare to move a dead body found in a sink-hole on a road on May 21, 2013. Five people died when a 33 feet wide sink-hole opened up at the gates of an industrial estate in Shenzhen, the southern Chinese boom town neighbouring Hong Kong AFP/Getty Images Sinkholes around the world Chicago, Illinois Workers prepare to pull a truck from a sink-hole that opened up on a residential street in the South Deering neighborhood on April 18, 2013. The driver of the truck was hospitalized after driving into the 15-feet-deep hole while on his way to work. Two other vehicles were also swallowed by the sink-hole Scott Olson/Getty Images Sinkholes around the world Guangzhou, China Workers use machinery to fill in a sink-hole that buildings collapsed into near a subway construction site. The hole measured about 1,000 square feet across and was around 30 feet deep, but no one was killed, according to a state media report STR/AFP/Getty Images Sinkholes around the world The Dead Sea, Israel sink-holes created by the drying of the Dead Sea, near Kibbutz Ein Gedi, on November 10, 2011 Menahem Kahana/AFP/Getty Images Sinkholes around the world Guatemala City, Guatemala A man inspects a sink-hole formed in a house on July 19, 2011 in the north of Guatemala City. When neighbors heard the loud boom overnight they thought a cooking gas canister had detonated. Instead they found a deep sink-hole the size of a large pot. The sink-hole was 40 feet deep and 32 inches in diamete Johan Ordonez/AFP/Getty Images Sinkholes around the world Beijing, China Workers use excavators to fill in a sink-hole which occured overnight on Shiliuzhuang road, in Beijing on April 26, 2011. A section of the road collapsed beneath a truck, slightly injuring the driver and a passenger, who both jumped out of the vehicle before it sank into the hole STR/AFP/Getty Images Sinkholes around the world Chevy Chase, Maryland Utlity workers examine the scene of a car caught in a sink-hole caused by a broken water main, which collapsed part of Friendship Blvd. on December 3, 2010. No one was reported injured in the accident Logan Mock-Bunting/Getty Images