# Civil defence, who is actually in charge when it goes wrong

Christchurch learned this system the hard way. When the quakes, floods or fires arrive, a statute takes over: the Civil Defence Emergency Management Act 2002. It decides who may declare a state of emergency, what powers that unlocks, and who coordinates whom, and on an ordinary day it is the reason the sirens get tested and the phone alert drills arrive.

## What it is

The **CDEM Act 2002** organises emergency management around the **4Rs**, reduction (stop it happening), readiness (be ready when it does), response (deal with it), and recovery (put it back). Emergencies here include anything that may cause loss of life or serious harm and can't be dealt with by normal services, quakes and floods, yes, but also infrastructure failure and human-caused events, [CDEM Act 2002](https://www.legislation.govt.nz/act/public/2002/0033/latest/whole.html).

The Act deliberately splits the work: planning and preparation happen every day at two levels, while emergency *powers* sit dormant until someone lawfully switches them on.

## Who's in charge

- **NEMA**, the National Emergency Management Agency, inside the Department of the Prime Minister and Cabinet. It runs the national picture: the Emergency Mobile Alert system, national warnings, and the machinery behind a state of national emergency.

- **CDEM Groups**, sixteen regional collectives made of the councils in each region. Canterbury's Group is a joint committee of the region's councils, coordinating through Environment Canterbury, this is why a flood in Ashburton and a tsunami sirens test in New Brighton are the same system.

- **Council CDEM units**, each council keeps its own emergency management staff and controllers, the people who actually know which bridge washes out first, [CCC, Civil Defence Emergency Management](https://ccc.govt.nz/services/civil-defence).

## The state of emergency

A **state of local emergency** can be declared by a person the CDEM Group appoints for the job under section 25, or by a **mayor** for their district, or a designated elected member standing in. The Minister can declare one nationally, and only the Minister (or a person they authorise) can declare a **state of national emergency**. Declarations last seven days and can be extended, and a local one can't be called over ground already under a national emergency.

What it unlocks: the power to **evacuate** people and keep them out, **close roads and public places**, **requisition** property and equipment, enter land and buildings, and direct people to stop activities that make things worse. It is the legal difference between "please leave" and "you must leave", [CDEM Act s68, declarations](https://www.legislation.govt.nz/act/public/2002/0033/latest/DLM150778.html).

The precedent this city knows: on 23 February 2011 the government declared a **state of national emergency** for the Canterbury earthquake, the first ever called under the Act. Kaikōura's 2016 quake ran on local declarations; Cyclone Gabrielle in 2023 was the third national one.

## The siren and the phone

Warnings arrive through several channels at once, by design:

- **Emergency Mobile Alert**, a cell broadcast to every capable phone in the threatened area. No app, no signup; if your phone is on and in range, it screams. NEMA and authorised agencies send them; the national test arrives yearly.

- **Tsunami sirens**, fixed sirens along the Christchurch and Banks Peninsula coast, tested twice a year. A siren is the signal to check official channels, not itself the instruction.

- **Radio, TV and official channels**, the formal word comes through broadcast media, council channels and [getready.govt.nz](https://getready.govt.nz).

## The zones

Christchurch's coast is divided into **three tsunami evacuation zones**, red, orange and yellow, modelled by GNS Science and NIWA and extended after remodelling showed large South American and Kermadec-source tsunamis could reach further inland than the old maps allowed:

- **Red and orange**, evacuate immediately on a **long or strong** earthquake (if it's hard to stand or lasts over a minute, go, don't wait for a warning), on instruction from Civil Defence, or when the sirens sound.

- **Yellow**, the biggest-ticket scenario; evacuates only on an official warning naming it, [Newsline, new tsunami evacuation zones](https://www.newsline.ccc.govt.nz/news/story/new-tsunami-evacuation-zones-for-christchurch).

The rule that matters most needs no map: **long or strong, get gone**, a near-source tsunami arrives before any warning can.

## In Christchurch

The zone checker, type your address, see your zone, lives at [ccc.govt.nz/services/civil-defence](https://ccc.govt.nz/services/civil-defence), alongside the city's community emergency hubs (pre-identified gathering points in suburbs). On this site the [civil defence feed](https://www.chch.live/civil-defence) carries the council's live emergency layer, road closures, event areas, notices, uncapped and pinned whenever it's active; the [warnings feed](https://www.chch.live/warnings) carries MetService watches and warnings, and [quakes](https://www.chch.live/quakes) logs every shake big enough to have been felt here.

## Primary sources

- [Civil Defence Emergency Management Act 2002, legislation.govt.nz](https://www.legislation.govt.nz/act/public/2002/0033/latest/whole.html)

- [National Emergency Management Agency](https://www.civildefence.govt.nz)

- [Get Ready, NEMA's public preparedness site](https://getready.govt.nz)

- [Christchurch City Council, Civil Defence Emergency Management](https://ccc.govt.nz/services/civil-defence)

- [Newsline, Christchurch's tsunami evacuation zones](https://www.newsline.ccc.govt.nz/news/story/new-tsunami-evacuation-zones-for-christchurch)

## The language

- **The 4Rs**, Reduction, readiness, response, recovery, the cycle the Act organises all emergency work around.

- **CDEM Group**, The regional collective of councils that coordinates civil defence, Canterbury's runs as a joint committee through ECan.

- **NEMA**, The National Emergency Management Agency, the national layer inside DPMC, sender of Emergency Mobile Alerts.

- **State of emergency**, The legal switch that unlocks evacuation, closure and requisition powers, local (Group-appointee or mayor), or national (the Minister).

- **Emergency Mobile Alert**, The cell-broadcast alarm to every phone in a threatened area, no signup, no opt-out that matters.

- **Controller**, The person who directs the response while a state of emergency runs, Group or local, as the declaration names.

- **Long or strong, get gone**, The self-evacuation rule for near-source tsunami, the shaking is the warning; official word comes after.

- **Community emergency hub**, A pre-mapped neighbourhood gathering point, where the city's plan expects people to self-organise first.

## The Canterbury of it

Everything above is the system this city stress-tested. The sequence opened at 4.35 a.m. on 4 September 2010 with the magnitude 7.2 **Darfield earthquake**, centred on the plains west of the city, larger than what followed, and deadly to no one, because it came in the dark. At 12.51 p.m. on 22 February 2011 a magnitude 6.2 struck directly beneath the city and the Port Hills on a fault nobody knew existed. **185 people died**; 115 of them were in one building, the CTV building on Madras Street, [NZ History, Christchurch earthquake kills 185](https://nzhistory.govt.nz/page/christchurch-earthquake-kills-185).

The powers described above did the visible work: a fenced cordon held the central city empty for more than two years while demolition ran, and suburbs drowned in liquefaction silt along the Avon/Ōtākaro were later written off entirely, the red-zone buyout mechanics sit on the [housing page](https://www.chch.live/how-nz-works/housing). The shaking did not stop politely: a magnitude 6.0 on 13 June 2011 and another pair on 23 December kept the sequence running through the year, with aftershocks in the thousands, [Te Ara, Canterbury earthquakes and rebuild](https://teara.govt.nz/en/canterbury-region/page-17).

The physical record is quieter. The 185 white chairs on the CTV site mark the dead; the [quakes feed](https://www.chch.live/quakes) on this site still logs every shake large enough to feel.

Last reviewed 2 October 2026, sources: legislation.govt.nz (CDEM Act 2002, s68), civildefence.govt.nz, getready.govt.nz, Christchurch City Council's civil defence and tsunami-zone pages, Newsline. Corrections: [/corrections](https://www.chch.live/corrections).

Keep reading

- [Local government, what councils actually do](https://www.chch.live/how-nz-works/local-government)

- [Health, who pays when you are sick](https://www.chch.live/how-nz-works/health)

- [Public transport, who runs the buses and what a ride costs](https://www.chch.live/how-nz-works/transport)

## Questions, answered briefly

**Who can declare a state of emergency in New Zealand?**, Locally, a person the CDEM Group appoints for the job under section 25, or a mayor for their district, or a designated elected member standing in; only the Minister, or someone they authorise, can declare a state of national emergency. Declarations last seven days and can be extended, and a local one can't be called over ground already under a national emergency.

**What powers does a state of emergency unlock?**, The power to evacuate people and keep them out, close roads and public places, requisition property and equipment, enter land and buildings, and direct people to stop activities that make things worse, the legal difference between "please leave" and "you must leave".

**When should I evacuate for a tsunami in Christchurch?**, In the red and orange zones, go immediately on a long or strong earthquake, hard to stand, or lasting over a minute, on instruction from Civil Defence, or when the sirens sound; the yellow zone evacuates only on an official warning naming it. The rule that needs no map: long or strong, get gone, because a near-source tsunami arrives before any warning can.

**What is the Emergency Mobile Alert?**, A cell broadcast to every capable phone in the threatened area, no app, no signup; if your phone is on and in range, it screams. NEMA and authorised agencies send them, and the national test arrives yearly.

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The laid-out original: https://www.chch.live/how-nz-works/civil-defence