A powerful 7.2-magnitude earthquake struck off Japan's northern coast on Thursday, although authorities quickly confirmed there was no risk of a tsunami.

The Japan Meteorological Agency initially reported a tremor of magnitude 6.9 before upgrading it to 7.2, locating its epicentre off the eastern coast of Iwate prefecture at a depth of about 50km. The US Geological Survey also recorded a 6.9 magnitude.

The region has experienced repeated strong earthquakes in recent months, with a powerful tremor in December prompting a week-long “mega-quake caution” advisory.

The latest quake struck during the morning rush hour and also caused mild tremors in Tokyo. Minoru Kihara, the top government spokesperson, confirmed there were no immediate reports of injuries or significant damage.

Prime minister Sanae Takaichi said her government's emergency team was "putting people’s lives first" as they assessed information and prepared for potential relief operations.

She advised residents in affected areas to remain vigilant for aftershocks.

Tomoko Nagane, a primary school principal in Hashikami, Aomori prefecture, recounted to NHK feeling moderate sideways shaking while driving when the alert sounded.

Although some children at her school were crying in fear, they were safe, and classes were cancelled for the day, with all pupils sent home safely.

NHK featured journalists from heavily impacted towns like Sendai and Morioka, who reported feeling the tremor for a couple of minutes but observed no visible damage.

Commuters were shown proceeding with their routines as normal.

East Japan Railway temporarily suspended some bullet trains and local lines in the northeastern regions for safety inspections.

Nuclear facilities, including the Fukushima Daiichi plant, which was severely damaged in the 2011 earthquake and tsunami, and a spent fuel reprocessing plant in Aomori reported no abnormalities following Thursday's event, Mr Kihara confirmed.

Japan, situated on the seismically active Pacific Ring of Fire, remains one of the world's most earthquake-prone nations.