TOKYO (AFP) - A 5.5-magnitude earthquake hit Japan's northern island of Hokkaido on Thursday (Feb 21) but no tsunami warning was issued, US and Japanese authorities said.

There were no immediate reports of damage or injuries from the quake, which occurred at 9.22 pm (8.22pm Singapore time) at a depth of 41km, according to the US Geological Survey.

The epicentre of the quake was around 55 km southeast of the city of Sapporo, the USGS added. The Japanese meteorological agency said there was no tsunami risk following the jolt.

"The government is doing its best to grasp the situation, but so far there has been no report of major damage," Chief Cabinet Secretary Yoshihide Suga told reporters in Tokyo in the immediate aftermath.

No abnormality was detected at nuclear plants in the region, Suga said, adding that the government was prepared to mount rescue operations if required.

Shinkansen bullet train services were temporarily suspended in Hokkaido but no major blackout was reported. Footage from public broadcaster NHK showed lights flickering on and off in a town close to the epicentre.

In September last year, a powerful 6.6-magnitude quake in rocked Hokkaido, triggering landslides, collapsing houses and killing more than 40.

Japan sits at the junction of four tectonic plates and experiences a number of relatively violent quakes every year.

But rigid building codes and strict enforcement mean even strong tremors often do little damage.