New Zealand 'will give gunman nothing - not even his name', Jacinda Ardern vows

New Zealand's prime minister has promised to deny the mosque terror attacker notoriety, saying she will never refer to him by name.

Jacinda Ardern was speaking as parliament met for the first time since 50 people were killed in Christchurch on Friday.

"He sought many things from his act of terror, but one was notoriety - and that is why you will never hear me mention his name", said Miss Ardern.

"We in New Zealand will give him nothing - not even his name," she added.

There are concerns that the suspect - believed to be behind a lengthy "manifesto" published before the attack - could use his court appearances to publicise far-right views.

Miss Ardern also warned social media companies they could face action, after the gunman broadcast his mass murder live on the internet.

YouTube and Facebook say they have taken down millions of versions of the video but have been criticised because the clip can still be accessed.

:: YouTube removes videos celebrating mosque attacks

The PM said told parliament she would look at what could be done "on the international stage and in unison with our partners".

"We cannot simply sit back and accept these platforms exist and what is said on them is not the responsibility of the place where they are published - they are the publisher, not just the postman.

"There cannot be a case of all profit, no responsibility," warned Miss Ardern.

The solemn session of parliament began with a prayer recited by an imam in Arabic, with the verses repeated in English.

Brenton Tarrant has so far been charged with one count of murder and Miss Ardern reassured parliament more would follow, saying he would face the full force of the law.

Police will also remain at mosques across New Zealand for the time being.

The PM said there was no specific threat, but that "security and intelligence services are receiving a range of additional information" that is being taken "extremely seriously".

An investigation into intelligence leading up to the attacks "will examine what we did know, could have known, or should have known", she said.

The suspect, who travelled the world extensively in the years before the attack, is understood not to have been on intelligence watch-lists.

"A frank examination" of New Zealand's gun laws will mean "our gun laws will change"," confirmed the PM - with the outcome due next week.

It comes after questions on how the killer appeared to easily amass his weapons, with a gun shop owner saying on Monday that he sold Tarrant guns online after he passed police checks.

:: How strict are New Zealand's gun laws?

Miss Ardern also recalled the heroism of people on the day of the attack.

She spoke about the two police officers who "rammed the vehicle from which the offender was still shooting", and people who tried to wrestle away the gun and throw a credit card machine at the killer.

Meanwhile, 30 people are still being treated at Christchurch hospital after the attack, nine of them are critical, said David Meates, head of the Canterbury District Health Board.

A four-year-old girl has also been transferred to an Auckland hospital in a critical condition.

Back in the UK, the Duke and Duchess have signed a book of condolence at New Zealand house.

They also laid bouquets of flowers outside the central London building.

The duchess was wearing earrings featuring crossed feathers, given to her by Miss Ardern.

They are also set to meet staff at the High Commission to talk about their response to the attack.