Constable Maude O'Connell said the 7am fire destroyed 61 Melmore Tce, which had been empty for years and was due to be demolished.
The property is on the corner of Melmore Tce and Achil St, opposite the Victoria Hotel at Old Cromwell Town.
No neighbouring properties were damaged and no-one was injured in the fire.
Cromwell chief fire officer Steve Shaw said two fire appliances and crews attended the fire, which was easily controlled and extinguished.
"It was just a very small, crib-sized sort of house and it was roughcast-clad so the fire was contained within the building. There was a small shed on the back of the property and that wasn't touched by the fire, so there was no worry about it spreading to other houses," he said.
The fire was one of several incidents police dealt with in Cromwell during the weekend.
The tyres of a car parked on Derry St, Cromwell, were slashed, a small digger situated within the town's industrial area was damaged, and an outside air conditioning and heating unit which was attached to a building was kicked in.
