The suspected airspace violation took place after 2:00 pm in south Porvoo.
Finnish Hornet fighter jet was dispatched to identify the aircraft.
Senior advisor to the ministry Kristian Vakkuri told news agency STT that if the case is confirmed, the incident will be the second airspace violation this year.
The first violation was by a Polish aircraft.
Six airspace violations were recorded last year five of which were committed by Russian aircrafts.
Vakkuri, however, refused to divulge more information.
The Finnish Border Guard is continuing with the investigation.
According to Finnish language daily Helsingin Sanomat, the sound barrier was broken at least in Asikkala and Karkkila.