The new close-off date for the 21,000ha scheme, located between the Waitaki River and Timaru in South Canterbury, is April 28.
Hunter Downs Water project manager Stacey Scott said the extension was to allow farmers and banks enough time to process paperwork for their applications.
She declined to say how many people were officially signed up or how many people were still being processed, but said the scheme was very much "alive".
The scheme design allowed for 161 water users, with a maximum of 214 offtakes. The water application rate would be 2.65mm per day.
The total projected cost for the scheme was $195 million, which equated to $9285 per hectare.
The scheme would be jointly funded by shareholders and ANZ Bank.
The shareholders would put up $2650 per ha and the rest would be raised by bank debt.
Mrs Scott said this was the last time landowners could access a reliable water source in the scheme’s catchment for the foreseeable future.
"This will be the last time we will be able to secure Waitaki River water to bring all the way to Timaru. A consent of this magnitude will not be gained again."
She said people might believe they could drill for water in the future or rely on tanks, but those options were not guaranteed to be reliable.
The chance the scheme sale would be extended beyond April 28 was small, she said.
"That’s our drop dead date. I don’t think the board will extend again."
