As the drought-like conditions tighten their grip in Canterbury and Otago, the national irrigation body has renewed its call for more alpine-fed water storage, to provide more reliable water supply.
Irrigation New Zealand said it had been advocating for alpine-fed water storage systems for well-over a decade.
That was dams and water storage lakes supplied by rainfall and snowmelt from rivers such as the Rangitata and Rakaia that flowed from the alps.
There were not currently many similar systems.
And with water restrictions increasing, Irrigation New Zealand chief executive Andrew Curtis said it was time to taker a more urgent look at water storage.
"The alpine water at the moment is mostly river takes, so most of the irrigation schemes take directly off the rivers. That was fine when they were built back in the 60s and 70s, but obviously we now have environmental legislation that sets out minimum flows on the rivers, which have crept up over time, so they now have periods where they're quite unreliable.
"So really the challenge now is how we actually supply a reliable water supply to them and also, as the climate has changed, and we've become more and more unreliable with the foot hill streams and some of the lowland streams, it's how we transfer some of those takes over onto alpine water as well."
Mr Curtis said investigations into increasing water storage were underway but they needed to happen quicker.
The biggest challenge was supplying the South Canterbury region, which currently had no access to alpine-sourced water.
"The South Canterbury dilemma is, where does the water come from and how much does it cost from each direction.
"So we've got the Tekapo option there, we've got taking water up from the Waitaki, which has storage in place already from the hydro dams, and the other option is letting water go south through the Rangitata.
"But we really need to work through, and quite quickly, what is the best and most affordable option and people need to stop saying that one option isn't achievable, when we haven't actually worked through what is the best and most cost effective solution."
Extending alpine-fed water supply into South Canterbury could increase the reliability of the region's Opuha water scheme.
The region's dam was at the lowest level seen for this time of year and the 250 farmers taking water from the scheme are down to 50 percent restriction with the likelihood of further cut-backs soon.
Chief executive Tony McCormick said boosting Opuha's supply from the Rangitata or Waitaki Rivers or taking a feed from Lake Tekapo to the west had all been considered as options under the Canterbury water management strategy, but there would be plenty of challenges to overcome.
"Just the logistics, both engineering wise and of course planning wise that are involved in schemes like that, are large and at the moment it's very much concept level.
"Rangitata has sort of emerged as certainly having water available and that's a fantastic outcome of a high level approach to looking at water across Canterbury. But again, there are logistical issues with that.
"Tekapo has historically been seen as the source because it's perched up there above South Canterbury and just over the hill, but there are a number of issues, including engineering and planning.
"And the Waitaki at the bottom, the main issue there is that it's a long way away and it's all up hill. So, none of those options are easy and they're definitely long term."