Residents in the central North Island town of Ohakune should be seeing water reappear in their taps again.

The supply's been without water since Sunday as a break in the town's main pipeline, caused by an earthquake last month, was repaired.

A boil water notice was in place as a precaution, while authorities test to see if the supply is safe to drink.

It was originally expected the water network would return to normal on Monday evening, but that was pushed out by 24 hours. The outage has caused schools and eateries in the town to close, and the Ruapehu District Council has provided a water tank, containers of water and portaloos for the town's 1400 residents.

Ruapehu Civil Defence controller Vini Dutra thanked Ohakune residents for their patience during the outage.

"Please continue to use water sparingly over the coming days so the reservoir can fully recover and pressure can be restored to normal levels," he said.

The council has asked residents to turn on outside taps and let them flow to help clear air from the pipes, while their inside ones were kept off.

"Taps may splutter when first turned on. This is just trapped air being released and is nothing to worry about," the council said.

"Water may also look milky. This is caused by air bubbles and is not a health concern. Low pressure may continue to be noticed until the reservoir has refilled several times."

What happened

The council's water services are contracted to Veolia.

A company spokesperson said on Tuesday afternoon the network was being flushed to make sure drinking water would be available as quickly as possible.

"The crack in the pipe caused by the earthquake remained undetected because no system data indicated a major leak," the spokesperson said.

"The leak was only discovered in dense bushland by a passing bush walker.

"Veolia took this seriously and responded immediately, as soon as it became aware of the crack, as this critical piece of infrastructure supplies water to the Ohakune Reservoir and is the town's only water supply," they said.

"If there had been a complete break it would have been far worse, with longer impacts."

Veolia worked quickly to repair the pipeline, in what it said was a hard-to-access area, and brought in extra staff from throughout New Zealand.

"The pipe was repaired quickly, but it is much more complex restarting the flow in a 7 kilometre-long, gravity-fed pipeline than simply switching on a garden hose.

"Air can become trapped if the water is simply switched back on at full capacity, which could cause pressure to build up and potentially lead to multiple breakages along its length."

The spokesperson said that air had to be cleared and the pipeline reopened in sections.

They thanked the community and said once the outage was resolved it would do a review of what happened and its processes.

On Tuesday, the council said it was too soon to answer questions about whether it could seek to fine or take other action against Veolia because of the outage, or whether closed businesses could get financial assistance.

"Far too early to answer that - we are still in response mode," a spokesman said.

"When the water is safely back on there will be a review of what happened ... and those issues will be looked at then."

School stays shut, businesses scramble

Ruapehu College stayed closed on Tuesday.

Principal Kris Vine said staff were staying in touch with the school's 250 students.

He was waiting on more information so he could plan the school's reopening, and communicate information to students' families.

"Most students are probably not too disappointed with not coming to school, to a certain extent, but I know that they'll be missing their mates and, obviously, there's the realisation of what water means to a community," he said.

"It's probably a nice little learning curve and a timely reminder about emergency planning and that kind of stuff for whānau that are dealing with it."

Students from places such as Waimarino or Raetihi weren't affected by the outage.

"I'm just here waiting for phone calls and checking in on any updates and things," Vine said.

"It's a nice little admin day, so to speak, but also a bit of a sit-and-wait kind of day, which is long."

At The Peaks Motor Inn, manager Remi Butler previously told RNZ the motel had taken a financial hit when a large group booking cancelled.

After the council confirmed the water would be out until Tuesday evening, she said she was disappointed and stressed by the news.

She said she and her husband were even contemplating buying a pump to get river water to flush toilets at the motel.

The motel did, however, have plenty of bottled water.