Southland is grappling with an extreme dry spell that's prompted water restrictions across the region and a total fire ban.

The Southland District moved into a prohibited fire season on Tuesday morning with all permits suspended until further notice.

NIWA figures showed Invercargill, Tiwai Point and Stewart Island had their driest summers on record, with the southern city receiving just 35 percent of its normal rainfall between December and March.

On Rakiura-Stewart Island, most residents rely on tanks fed by rain for their daily supply of water.

Community Board chair Jon Spraggon said they were getting awfully low after three to four months of virtually no rain.

He had been on the island for about three decades, and said it was the worst he had seen it.

"A few years ago, we had a couple of months - three months - and the ferns started to turn up their fronds and water was in short supply, and at that point a lot of people bought big water tanks.

"This time, even those people who bought the big water tanks are actually starting to run out of water."

Mainland solutions often did not work for the remote island.

"We can't get a water tanker in from outside. What happens here is our local fire brigade will deliver water that's not suitable for drinking but for toilets and stuff like that, that comes out of one of the local streams, out of the spring, and they've been flat tack delivering water."

It had been hard on commercial business, especially those who had to convince visitors used to living on a regular supply to conserve water, he said.

Across the Foveaux Strait, the Ōreti River remained the sole water supply for roughly 50,000 Invercargill residents as well as businesses and industry.

The Invercargill City Council has already banned unattended hosing and sprinklers - the first stage of water restrictions - for the first time since 2018.

Its Three Waters Strategic Advisor Alister Murray said the restrictions were triggered once the river flow fell to or below certain levels as part of its permit to draw water - and they were approaching the second stage.

"Then we have to ban all outside domestic use, which means you can't wash your car or even hold on to the hose. It's all banned.

"These restrictions have been put in place to protect the Ōreti River."

Work was underway to source an alternative supply so they were not left high and dry in an emergency.

"We are vulnerable by only having one source. We realise that and we want to develop a second source and one that won't be so susceptible to the sort of situations we have now.

"So we see that as being best served by an underground water supply."

Fly Fish Mataura owner Barry Perkins has been living near to the Mataura River for the past forty years - half in Gore and the earlier half as a dairy farmer further south.

"The biggest concern at the moment is some of the smaller streams are very, very weedy so if you do hook a fish in them, they end up in the weed and get stressed.

"You've got to be very careful handling fish, especially when the water's warm. We try to catch and release virtually everything so we don't want fish dying on us."

The lower river flow meant it was easier to find trout, he said.

"The one good thing out of it is that the low levels has opened up a lot of fishing areas that you can't normally wade to. You can walk across the river in a lot of places at the present time."

He recently went on a fishing trip to Fiordland, and said he had never seen the area so dry.

"Dairy farms out there that looked like they were in the middle of the North Island to be quite honest."

There was not enough grass to feed stock, he said.

"It is pretty grim for a lot of farmers out there at present, there's a lot of trucks going past here with baleage and hay on them so I think there's a lot of people buying food."

With NIWA predicting limited respite in the coming weeks, Southlanders were hoping the weather gods have something wetter in mind.

Republished by Arrangement