Serious consequences for intelligence agencies possible after Christchurch Royal Commission of Inquiry - Jacinda Ardern

Prime Minister Jacinda Ardern says there will be serious consequences for our intelligence agencies if a Royal Commission of Inquiry into the Christchurch terror attacks finds that appropriate.

On Monday, Ardern announced Supreme Court Justice Sir William Young will chair the inquiry, which will look into areas such as the alleged shooter's use of social media, his residence in New Zealand, and how he obtained a gun licence.

But it will also analyse what relevant intelligence agencies knew about the individual and what more they could have done to prevent the attack.

Ardern told The AM Show that if the Sir William believed there were other necessary areas of work not listed in the terms of reference, he had the power to recommend further lines of inquiry.

"[The purpose of the inquiry] is looking at the event. What we haven't ruled out, of course, is that the inquirer could say 'in the course of this work, I have concern around this wider issue, that I think is relevant to the attack, and I think additional work needs to be done'," she said.

After the attacks, it was announced that the alleged shooter wasn't on any watch list and, on Tuesday, Ardern wouldn't rule out serious consequences for intelligence agencies if the Commission finds that appropriate.

"Certainly, if that is what an inquiry finds, there needs to be consequences for that, but I am not pre-empting that."

There have also been questions about intelligence agencies' priorities and if they have been too focussed on threats coming from Islamic extremists.

One of the inquiry's terms of reference says it should question "whether there are any inappropriate concentration or priority setting of counter terrorism resources by relevant state sector agencies prior to this attack".

Ardern said she hopes the public recognises the Government, as well as the agencies themselves, wants answers to these questions.  

"We have actually asked the inquirer were we looking in the right places. I hope people see we have listened to people's concerns, we have asked the inquirer to look in those areas," she said.

"Those agencies themselves want this inquiry, they want to be able to have a mechanism to give assurances to the public or to fix if there are mistakes that have been made."

With a budget of $8.2 million, the inquiry will begin considering evidence on May 13 and must report back by December 10.

Ardern said while Kiwis will want answers soon, timeliness must be balanced with getting the right information.

"There is that demand for it to be delivered sooner rather than later.

"We want to learn those lessons quickly, so we can be sure that if there is anything we should be doing different, we move on it."

Security expert Paul Buchanan told Newshub the inquiry is appropriately thorough.

"It will establish, not only [the shooter's] motivations, but whether or not he acted alone, and that in itself will take a considerable amount of resources," he said on Tuesday.

"That is focussed on the agencies that should have been monitoring him - the SIS, the GCSB, the Police - so it makes for a fairly expansive inquiry."

But he also hopes the process will be open and transparent.

"Police, the GCSB and the SIS have a long history of redacting information on the grounds of national security. So we have to be aware of the possibility of a whitewash."

Newshub.