Tsunami waves of up to 50 centimetres were expected to reach the coasts of Iwate and Aomori prefectures at 6:40 pm (0940 GMT), the agency said.
The quake occurred at 6:09 pm with an epicentre off Aomori prefecture at a depth of 10 kilometres, the agency said.
No injuries or damage were reported.
A magnitude-9 quake and tsunami hit north-eastern Japan on March 11, 2011 leaving more than 15,800 dead and nearly 3,300 missing.//DPA