Police said the car in which the migrants were packed had another vehicle's license plates and is suspected of having been used for migrant trafficking.
The car had not stopped at a police checkpoint during its journey, but it wasn't immediately clear how close to the site of the crash that it happened.
Police said the crash occurred just after 5 am (0200 GMT) near the town of Kavala.
The car, which had been heading to the main northern city of Thessaloniki, collided with a truck heading in the opposite direction and burst into flames.
All of the victims have been burned beyond recognition. The truck caught fire as well.
Greek authorities have been seeing an increase in people illegally crossing the Greek-Turkish border in recent months.
Many are transported to Thessaloniki, where they head to police stations to be registered and apply for asylum.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)