Climate change is tipped to alter Wairarapa wines for the better but unpredictable temperatures are proving a challenge for those in the farming industry.

New Zealand's climate is changing with long-term trends towards higher temperatures, more hot extremes, fewer cold extremes, and shifting rainfall patterns in some regions, according to the New Zealand Climate Change Centre.

National Institute of Water and Atmospheric Research (NIWA) data shows New Zealand's average annual temperature has already increased by about 0.9C over the past 100 years.

The districts of Wairarapa have a strong primary sector focus, according to the Ministry of Business, Innovation and Employment's (MBIE's) Regional Economic Activity Report 2015.

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It said there was an above-average concentration of employment in sheep, beef cattle and grain farming, particularly in the South Wairarapa and Masterton districts.

South Wairarapa had a relatively high concentration of employment in viticulture, the report said.

Wairarapa had long been a sheep farming centre, although there had been increasing conversion to dairy in recent years as well as vineyard planting on the gravelly plains, and forest planting in the hills.

Lincoln University senior lecturer in viticulture Dr Glen Creasy said the changing climate could influence harvest times and wine styles.

"In Australia, they've done actual research on this and it's very definitely been advancing harvest dates in Australia so there's no reason to think it would be any different in New Zealand."

Increasing summer temperatures would mean a warmer growing season for grapes.

"It'll change the composition of the fruit so the flavours and the kinds of wines that can be made from the fruit will shift over time and so they'll probably have to change the way they manage the vines in order to keep the wine style that they want to produce the same.

"That's something that's already being done but it's a matter of being proactive rather than reactive."

Some wine styles were dependent on cooler weather and temperature increases might mean particular wine styles couldn't be made over the next 50 to 100 years, he said.

The warmer summer temperatures might also mean people could produce wine styles they couldn't reliably make now.

"If the managers are on top of things then it should mean, within a certain range anyway, that it will overall improve the quality or quantity of the fruit and the harvest."

Dr Creasy said less frequent but more severe frosts could also be a big concern for the industry.

"If you have frosts occurring that you cannot control and they occur too many times then it just doesn't become viable for the business to operate that way, so that may see some people shifting around a little bit as those frost events come in and people find out how bad they are.

"The one thing that's for sure, well at least in my opinion, is the risks associated with producing grape vines and grapes for wine are going to increase and so management will have to adjust to that."

University of Waikato professor of agribusiness Jacqueline Rowarth said farmers were "absolutely" aware of climate change and were trying to adapt to it.

"Farmers get a bad press. Farmers are doing everything they can to set up their businesses in a resilient fashion and cope with what is going on," Dr Rowarth said.

The unpredictability of the weather was a challenge for farmers and they were preparing for weather events which may or may not happen, she said.

"I think the worst thing is drought, and the unpredictability of where the water is going to be has been impacting us for some time."

She said a proper water debate needed to take place in New Zealand, which wasn't happening.

"We haven't reached the state of maturity that the debates can happen without the emotion that's rife.

"If you haven't got water then you can't grow grass so what are we going to do?"

Dairy farmers had installed shelters to keep animals cool and provided efficient ways of feeding animals when there was no grass, said Dr Rowarth.

Farmers were also converting to dairy because it was easier to manage the environment for dairy than for beef and sheep.

"I think farmers have done a heap and the industry bodies are trying to help with the consideration of options but we do have animal welfare and of course human welfare, environmental welfare, all of those things to consider at once," she said.