A giant sinkhole appeared on a main road in downtown Fukuoka - located on Japan's Kyushu Island - on Tuesday (Nov 8) morning, disrupting traffic and causing power failures.

Local media reports, quoting police and city officials, said the road caved in near the busy Hakata at around 5.15am local time.

No immediate injuries were reported.

The site of the collapse was an area where construction work was ongoing to extend Fukuoka city's subway system, according to The Japan Times.

By 9am, the sinkhole has grown to cover 20m in every direction, and photos showed that the entire road intersection was impassable.

Some 800 households were affected by outages, although power was progressively restored throughout the morning.