Last update: 7:15pm
Forty-nine people have been killed and more than 20 seriously injured in mass shootings at two mosques in the city of Christchurch in New Zealand with multiple fatalities reported.

Police Commissioner Mike Bush confirmed 49 people died in attacks, 41 at the Masjid Al Noor mosque, located in the city centre opposite Hagley Park, and seven in a second attack on a mosque in Linwood Avenue to the east of the city centre. One person died in hospital. 

Jacinda Ardern

New Zealand Prime Minister Jacinda Ardern speaking at a press conference in the wake of the attacks. PICTURE: Screenshot.

Four people, including one woman, have been arrested. One of them has been confirmed as an Australian-born citizen.

Police Commissioner Bush confirmed a male aged in this late 20s has been charged with murder and will appear in court tomorrow. He said it was believed one of the others arrested with a firearm at the scene may have had nothing to do with the incident and police were working to understand the involvement of the other two arrested.

Bush confirmed two improvised explosive devices were found on one vehicle and that one has been defused and the other was in the process of being diffused. 

Prime Minister Jacinda Ardern condemned the attacks at a press conference late on Friday.

"It is clear that this can now only be described as a terrorist attack," she said. "From what we know it does appeared to have been well-planned..."

She said New Zealand was not chosen for the attacks because it was an "enclave of extremism" but because "we represent diversity, kindness, compassion, a home for those who share our values, refuge for those who need it and those values, I can assure you, will not and cannot be shaken by this attack". 

Ardern described the attackers as people who have "extremist views" which have "absolutely no place in New Zealand and, in fact, no place in the world".

"You may have chosen us, but we utterly reject and condemn you."

Witnesses have described how a gunman walked into the mosque in Deans Avenue on the western side of Hagley Park at about 1:45pm while hundreds of people were at Friday prayers and opened fire indiscriminantly with what was reported as a machine-gun.

At an earlier press conference, Ardern said it was "clear that this is one of New Zealand's darkest days".  

She said many of those who may have been affected may have been migrants or refugees who had chosen to make New Zealand their home.

"There is no place in New Zealand for such acts of extreme and unprecedented violence..." she said.

She said the attack has occurred in a place where people should have been safe.

She said perpetrators of such acts "had no place in New Zealand society".

Confirming one of those arrested was an Australian-born citizen, Australia's Prime Minister Scott Morrison said he was "appalled and sickened" by what he described as a "terrorist attack".

Describing New Zealanders as "family members" and "cousins", he said "we stand here and condemn absolutely the attack that occurred today by an extremist, right wing, violent terrorist".

Police have asked people not to attend mosques in New Zealand today. A lockdown of schools in Christchurch was lifted shortly before 6pm local time.

New Zealand Police also said they were attempting to remove a video of a live-stream of the shooting at the Al Noor mosque which had appeared on social media.

The Bangladeshi cricket team were reportedly about to enter the mosque when the shooting began but were warned off before they entered.

New Zealand's national security level has been lifted from 'low' to 'high'.