The Earthquake Observation Division of the department said the epicentre of the quake, which happened at 2.30pm, was in Tambon Wiang Nua of Pai at a depth of 2 kilometres.
Officials said the tremors were felt by several districts of neighbouring Chiang Mai province, prompting Governor Nirat Pongsitthavorn to order all concerned local administrations in the province to rush out to survey the damage.
The division added that there was an aftershock of 2.4 magnitude, also in Tambon Wiang Nua, at 2.42pm.
The Chiang Mai Disaster Prevention and Mitigation Office reported that tremors were felt in Mae Taeng, Samerng, San Sai, Mae Rim and Muang districts.
The office added there were still no reports on damage and injuries.