The epicentre of the earthquake lay at the depth of 34 miles (56km), while the tremors could also be felt in Athens.
The authorities have reportedly ordered to evacuate schools and universities.
"Earthquakes at this depth are normally single events and are not followed by many aftershocks. So there is no serious cause for concern,'' Efthimis Lekkas, head of Greece's Earthquake Planning and Protection Organisation, said.
Greece lies in one of the most seismically active parts of the world. The tremors come a day after a powerful 6.4 magnitude earthquake hit Albania leaving 21 people dead.