The historic stone cottage has been restored in a joint project between the Weston Progress League and the Waitaki District Council.
Joseph Kelly bought sections 16 and 17 from the Australian and New Zealand Land Company at the auction of Weston Park in 1881.
The cottage stands on part of section 17 and might have already been built in 1881.
John Robertson bought the property in 1901 but might have already been living with his family in the extended dwelling.
After he was killed in a horse-and-trap accident his widow Janet and her five children continued to live there.
They owned the property until 1937.
Messrs Kelly and Robertson quarried stone at Weston for about 30 years and owned a quarry together.
Members of the Robertson family attended yesterday's official opening.
Weston Progress League chairman Derek McGee said a lot of work had been done by voluntary labour, including renewing the foundations, floor, roof, windows, fencing, drainage and garden.
He especially paid tribute to the work of John Walker, Gordon Hay and Ross Mitchell, and to Mr Mitchell's wife Ainslie who was "undoubtedly" the driving force and passion behind the project.
Deputy mayor and Weston resident Gary Kircher said Mrs Mitchell saw beyond the derelict building and talked to the council about coming up with a solution as to how the cottage could be "sorted out and tidied up".
It had been abandoned and the council no longer collected rates off it.
The cottage was put under the care of the Weston Progress League.
Mr Kircher congratulated everyone involved in its restoration, saying there was now an asset in the main street of Weston which was previously an eyesore.
