But Leaning Rock Village Trust chairman Russell Checketts said he hoped the extension would be the last needed, and progress would finally be made securing land for the project.
Leaning Rock wants to build a not-for-profit retirement village on the outskirts of Alexandra to the east of State Highway 8, beside the Molyneux Estate subdivision.
Part of the land earmarked for the development is a 4.2ha area of freehold Central Otago District Council land and the other part is Crown land, which will be offered to Ngai Tahu.
The trust was hoping to negotiate with Ngai Tahu to buy the land, but statutory processes transferring the land to Ngai Tahu had been incredibly slow, Mr Checketts said.
The Vincent Community Board has already agreed five times to delay any further development interests in the council land while Leaning Rock is still in negotiations for the Crown land. The first extension was granted in 2014 and the most recent in February this year.
The board this week agreed to a sixth extension, and Mr Checketts said trust members were "appreciative" of the board's support.
"We're totally powerless [over the timeframe for the land transfer] and have no control over the process," Mr Checketts said.
"All we can do is request another extension. Hopefully, things will proceed and we will be in a position where next time we can come [to the board] and give you some progress."
The offer of the land to Ngai Tahu was now thought to be "imminent", Mr Checketts said.
Council property and facilities manager Mike Kerr said transferring the Crown land had "definitely" taken longer than other transfers, as the land was held under an "unusual piece of legislation".