Prime Minister Jacinda Ardern says the national security level has raised to high after dozens were killed and injured in a terrorist attack in Christchurch.
Here's what you need to know.
At least 49 people have died in the Christchurch shootings, seven at Linwood Masjid Mosque and 41 at Masjid Al Noor Mosque next to Hagley Park on Dean Ave mosque.
More than 20 people are seriously injured and one has died in Christchurch hospital.
It has been described by the Prime Minister as a terrorist attack, and that it was well planned.
RNZ has confirmed a person in custody is Brenton Tarrant.
What are the authorities saying?
A man is his late 20s has been charged with murder and will appear in court on Saturday morning.
Police initially said four people were arrested. Three connected to the attack remain in custody, of them one is a woman. They cannot confirm if there are other people involved.
The Prime Minster said one of people arrested is not connected to the attack.
Australian Prime Minister Scott Morrison has confirmed an Australian is among those arrested.
The Prime Minister said those in custody were not on any security watch lists.
Police said two improvised explosive devices found attached to one vehicle, and weapons were found near both the mosques.
Christchurch Hospital is treating 48 people for gunshot wounds. Patients range from young children to adults, and injuries range from critical to minor.
St John said it has transferred multiple patients to Christchurch Hospital and local medical facilities.
It said as well as multiple fatalities, patients have injuries ranging from critical gunshot wounds to minor injuries.
Police are urging people in central Christchurch to stay indoors and report any suspicious behaviour immediately to 111.
Police said a facility is being set up so people can get information about family members who may have been harmed.
What's in lockdown?
Addresses near a property on Sommerville Street, Dunedin have been evacuated as police attend.
Schools were in lock down since the attack on two Christchurch mosques shortly before two, but pupils have since been allowed to go home.
Police said all mosques nationally to shut their doors, that people should not visit them until further notice.
Christchurch Hospital remains in lockdown, with no staff or patients able to enter or leave the buildings.
They said the public should not go to the hospital unless it's an emergency.
All council buildings in the central city are in lockdown.
What roads are closed?
Around the Deans Ave mosque Blenheim Road is closed between Clarence Street and Deans Ave, Deans Ave is closed south bound, Moorhouse Avenue is closed westbound on Lincoln Road, Moorhouse Avenue closed from Lincoln Road to Deans Avenue, Riccarton Avenue closed westbound from Hagley Avenue, and Riccarton Road closed east bound from Clarence Street.
St Asaph Street and Hagley Avenue are now open.
Around the Linwood Avenue mosque Linwood Avenue is closed between Aldwins Road and Worcester Street, and Cashel Street closed eastbound to Linwood Ave.
At the site where several people were arrested on Brougham Street there are also still some road closures in place.
Blenheim Road is closed eastbound from Clarence Street, Moorhouse Avenue closed westbound from Montreal Street, Christchurch Southern Motorway closed eastbound from SH73 / SH75 at the Curletts Road interchange, SH76 Brougham Street closed westbound from Waltham Road, Montreal Street closed southbound between Moorhouse Avenue and Brougham Street.
On Durham St there is no west bound access to Brougham Street between Durham Street and Barrington Street.
How's transport affected?
Air New Zealand has cancelled 17 regional turbo prop services in Christchurch this evening, but jet operations are continuing.
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Missing persons can also be registered on 0800 115 019. A member of the police will be in contact thereafter.
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