Unidentified arsonists damaged the political office of Merchant Marine Minister Miltiadis Varvitsiotis in Kolonaki, central Athens, on Wednesday night.
The assailants broke into the ground-floor office and doused it with petrol before fleeing on foot, witnesses said.
The fire service doused the resulting blaze, according to police who said they were seeking the perpetrators.
The two employees in the office at the time of the raid were forced out by the arsonists. They were not hurt.