Built in 1865, the flour mill near Maheno has opened for visitors for the summer season.
It will be open every Sunday from October 25 until April 25, between 1pm and 3pm.
In a new initiative this year, the machinery will run on the last Sunday of each month about 2pm.
Restoration of the mill - once one of 13 in North Otago, and the second-oldest - has been a labour of love for a small group of dedicated men who, for the past few years, have been bringing it back to life.
Dave Clark, whose grandfather David Clark was one of four brothers who bought the flour mill in 1901 from the New Zealand and Australian Land Company, said the machinery operated "every now and then" - "just for the mill's sake".
Due to public demand and the installation of safety barriers, it was decided to run the machinery monthly, although flour was not being milled.
"It gives it purpose and life," Mr Clark said.
Like Nicols Blacksmith Shop at Duntroon, Clarks Mill was an integral part of North Otago's heritage, retired architect Harry Steenson said.
The district was once one of the largest wheat-growing areas in New Zealand and its wheat was exported to Australia, shipped from Oamaru Harbour.
The aim was to make the mill more accessible to the public and to also tell the "human side" of the story, Roger Blackburn said.
It was difficult to tell Oamaru's story without referring back to the early wheat-growing and agricultural days and the beauty of it was having an original building on an original site to build the true story around, he said.
The mill also opened for groups to visit and already had three groups booked in next month, including those attending the Australasian Heritage Engineering Conference.
The men are keen to receive any surplus flat belting.
