Surface and groundwater use in Rangitikei has increased in the past two decades but there is plenty more to go around.

Less than half the water available for irrigation is being used, signalling potential for increased irrigation in the district.

The Rangitikei Strategic Water assessment reports were released this week and Mayor Andy Watson said it was encouraging for the district's agricultural sector.

Rangitikei District Council and the Ministry for Primary Industries each put $100,000 into the study, and the Catalyst Group was commissioned to assess the use and availability of the resource.

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The report said the surface water take in Rangitikei had increased more than 100 per cent in the past 15 years but 39 per cent, or 110,000cu m a day, was still available.

The report also revealed the groundwater take was nowhere near capacity.

Horizons has set the maximum groundwater take limit at 5 per cent of the annual rainfall and currently there are consents to take a maximum of 92 per cent of that. However, only 24 per cent is actually used.

"There's a whole lot of water that has been consented to that is not being used," Mr Watson said.

"There is a huge amount of potential to use more water, in terms of both irrigation and stock water."

The report said: "In the last two decades, there has been a considerable increase in use of the region's surface and groundwater resources."

It came with warnings too, noting that increased use of ground water along the Rangitikei coast increased the risk of saltwater intrusion and impact on wetlands and lakes.

Also the groundwater supply had not completely replenished after each season over the past five years.

But Mr Watson said it was nothing to panic about and there was a lot more to learn about ground water in the region.

He said that, in the short term, progress could be made on some stock water projects but the next major step was more in-depth case studies of individual farms, examining the costs of irrigation and the estimated benefits.