Installed 140 years ago, the wheel is being given a new lease of life by the Phoenix Mill Restoration Trust, which was established about seven years ago by former North Otago resident Richard Pringle.
Work to restore the 10m-diameter wheel, being carried out by volunteers, started in early June.
In January, Waitaki Mayor Gary Kircher, a Phoenix Mill Restoration Trust trustee, said it was possible the project would be completed by the end of February.
However, a decision was made recently to construct a retaining wall behind the two stone walls that form a 4m-deep pit, which features some of the original stonework and will be lined with timber and reinforced with steel, that the wheel will be lowered into.
Mr Kircher said the wall was necessary to divert water run-off and debris from a nearby hill away from the pit.
"We've sorted out getting the stonework done, but before we could do that a retaining wall needed to be built behind it, so that's just been given the go-ahead. It's a late decision that's been decided as being beneficial."
There was no timeframe for the project's completion, which included landscaping at the site, Mr Kircher said.
The cost of the project is about $100,000.
The trust secured an $80,000 grant to fund it, and the Waitaki District Council committed $10,000 in September 2015 and another $10,000 as part of its 2017-18 annual plan.
