A group called Extinction Rebellion turned off water at the ECan offices and chained themselves to the water mains in protest to the way ECan has been dealing with Canterbury's water. (Video first published on December 20, 2018)

Five people have been arrested after shutting off the water supply to 500 staff at Environment Canterbury's headquarters.

About a dozen protesters sat chained over two Toby boxes that control access to the building's water mains, blocking access for more than three hours on Thursday.

At midday, 40 protesters, along with a dog named Sophie, marched through the St Asaph St office to take the water they believe the regional council is misusing.

"ECan has actively facilitated the expansion of industrial farming practices that are turning our rivers toxic, cutting down trees, killing soil life and emitting dangerous amounts of carbon into the atmosphere," they chanted.

"They have bypassed democratic process, allowing our water to be bottled and sold."

Just before 4pm, about 10 police officers arrived to remove and arrest those blocking one of the access points.

Senior Sergeant Paul Manhire said five people were arrested for "obstruction-type" offences.

"The building couldn't function. There were no toilets or drinking water for the staff and that'd been going on since just after one o'clock," he said.

"We asked them to move so the water could be turned back on. They refused."

DAVID WALKER/STUFF Extinction Rebellion has recently launched in Christchurch and is planning more protests and action against climate change.

Initially after the protest began, no staff at ECan appeared to be aware their water was shut off. No staff spoke to protesters either during or immediately after the chant.

The protest was organised by a new group named Extinction Rebellion, which argues political urgency over the world's climate crisis has now reached New Zealand.

"ECan, E coli, same bulls...," one sign read.

The protest was important for Sophie, the border collie, as well.

"She wants to swim in the Ashley River without getting sick," her owner said.

With no immediate action taken by ECan, Extinction Rebellion spokesman Rowan Brooks entered the building to deliver by hand the declaration to ECan chief executive Bill Bayfield. He was not in.

DAVID WALKER/STUFF A lone police officer responded to the initial ECan complaint, before about 10 later returned to make five arrests.

"He'll be coming back through about 2pm, so I'm sure he'll come and see you," reception staff told the protesters.

About 1.30pm two ECan staff members approached the protesters and asked them to turn the water back on. The water shut-off affected about 500 people working in the building.

They said the protesters could make an appointment to see Bayfield in the new year. The protesters politely refused.

"We don't expect an appointment with Bill [Bayfield] will make us heard. We are here so we're going to be heard," Brooks said.

"This is direct democracy," he told them. One of the staff members laughed and said "we know what we have to do".

DAVID WALKER/STUFF Rowan Brooks, centre, sits among other Extinction Rebellion protesters after they turned off water at the ECan offices and chained themselves to the mains.

Brooks, along with fellow activist Gen de Spa, was one of the five arrested.

Manhire said all arrested would not be held for long.

"The main thing was to put the water back on so that ECan can function ... these people have got a right to protest and we recognise that."

An ECan spokesman said they respected the group's democratic right to protest and had heard what they had to say.

"The protesters turned the water off, impacting on our ability to occupy the building. We've asked them to turn it back on. They've refused, and consequently we ... asked police to attend so that water can be restored," he said.