The homestead was the oldest established continuous rural homestead in the Wyong District, built by Charles Alison in the 1870s.
A spokesman for Tuggerah Lakes Police said the caretaker of the property noticed a glow at 3.20am and arrived on the scene to find three buildings alight.
Police said the caretaker reported seeing a man running from the scene.
The spokesman said firecrews were able to save little of the historic buildings.
Samples of blood and other materials have been taken from the scene and investigations into the fire continue.
Alison Homestead was set on two hectares in a rural setting on Wyong’s first land grant. It was extended when original owner Charles Alison married the grand daughter of Blue Mountains explorer, William Cox. The property passed out of the family in the 1890s and was used for market gardening between 1898 and the 1970s.
In recent times the property became a museum and home of Wyong District Museum and Historical Society.
