Hopes coronial inquiry into Christchurch terror attack will finally give affected families closure

A full coronial inquiry will take place investigating March 15 which some families hope will finally bring most of the answers they have spent more than three years asking for.

The coroner has laid out exactly what will be examined in the hearing including a proper look at all the victims' final movements and a thorough investigation of online radicalisation.

Aya Al Umari's brother Hussein was shot dead on March 15 at Al Noor mosque and she's spent three years battling various agencies to get the answers.

"We'll never get Hussein back but what we can get back is the story," she told Newshub.

"The most important thing for my family is to understand Hussein's last movements."

Whether anyone could have survived and the final movements of all 51 people killed will also be scrutinised by the coroner.

Until now, families have been largely left in the dark. Much of the Royal Commission of Inquiry into the attack was conducted in private because of the security and defence interests of New Zealand.

Abdur Razzaq, from the Federation of Islamic Associations, said this inquiry will hopefully give families the answers they have been looking for.

"There are a lot of questions in the community and hopefully this will be an opportunity to resolve those and bring closure to many families."

In the inquest, the coroner will also look at whether the terrorist had help from anyone else.  Some present at the attack are certain he did.

Gunman Brenton Tarrant's formal police interview, CCTV footage of the day and evidence from his weapons will be poured over - none of this has yet been made public.

The inquest will also drill down into the murderer's gun licensing process and online radicalisation - focusing on Tarrant's internet activity between 2014 and 2017, an area that the Royal Commission didn't investigate.

Coroner Bridgette Windley has already used her powers and asked Tarrant to disclose where his crucial hard drive is and if any information was uploaded to cloud storage.

Incredibly, the gunman's video recording of his attack on March 15 can still be found online.

"It's still up, it's still up last time I checked there's still about a dozen of them still up on Facebook and Instagram," said Eric Feinberg from Coalition for a Safer Web.

That's despite many attempts to make the internet a safer place including the Prime Minister's Christchurch Call.

The inquest will be held in Christchurch but the date is yet to be set.