CONCERNS have been raised that a historic windmill south of Campbelltown is falling into disrepair while a decision to list it on the state heritage register hangs in the balance.
The 180-year-old windmill tower is the last surviving remnant of a windmill cluster that dominated the local skyline for most of the 19th century.
It was built in 1834 by the ex-convict owner of Mount Gilead, Thomas Rose, originally to grind grain and it was reputed to contain the colony's finest millstones.
The windmill is on the site of a working dairy.
NSW windmill expert Ron Madden, of Wagga Wagga, wrote to Campbelltown mayor Clinton Mead in May calling for the tower to "be preserved as a matter of utmost priority".
"The Mount Gilead windmill tower is probably one of, if not the, most important parts of this state's industrial archaeology and staggeringly it is not on the State Heritage Register and it is, as we speak, deteriorating," Mr Madden said.
He said the tower's extremely rare concentric tapered walls, which were built using ashlar stone, are unique to Australian windmills.
In its local heritage listing with the Campbelltown Council, the windmill is described as being without sails but structurally sound.
The estate was first considered for the State Heritage Register in August 2008 and an Office of Environment and Heritage spokeswoman said although it was found to have significance it was not immediately listed.
She said any decision to list Mount Gilead on the State Heritage Register hinged on further research, currently being done. If successful, the Heritage Council would make a decision in the next year.
A listing would force the private owners of the estate to adhere to minimum standards of maintenance.
Mr Madden said protection was absolutely critical.