An artists' studio at the historic Keirunga Gardens in Havelock North has been damaged by fire and an adjoining flat destroyed.
The blaze broke out just before 11.30pm.
Up to nine fire crews from Hawke's bay battled the blaze.
A Fire Service spokesman said it took two hours to control the fire.
A specialist Fire Service investigator would be at the scene today to determine the cause of the blaze.
The neighbouring historic homestead and cottage were undamaged.
The flat tenant was not home at the time of the fire.