Post-mortems have been completed on all 50 victims of the Christchurch terror attacks.

In a statement, police said 12 victims have been identified to the satisfaction of the Coroner and six of those have now been returned to their family.

"Police are acutely aware of frustrations by families associated with the length of time required for the identification process following Friday's terror attack."

Investigators are also looking at improving their communications with families to ensure they are kept fully informed about what is happening.

"While identification may seem straightforward the reality is much more complex, particularly in a situation like this," the statement said.

"Our absolute priority is to get this right and ensure that no mistakes are made.

"We are doing all we can to undertake this work as quickly as possible and return the victims to their loved ones."

 

Earlier, ​Parliament's Speaker Trevor Mallard has led a multi-faith delegation into the debating chamber this afternoon for a special sitting of Parliament.

The procession came down the Speaker's Corridor and through the Grand Hall before going into the House.

Prayers were offered by each of the religious representatives, beginning with a Muslim prayer.

Statements of condolence, led by Prime Minister Jacinda Ardern, will be made before the House adjourns for the day.

Ardern told Parliament the 15th of March would now be a date etched in everyone's memories.

She also noted that it was "horrendous" that the mosque gunman's livestream of the shooting can still be viewed on Facebook.

The Government had been in contact with Facebook and said it was ultimately the social media giant's to remove it, she said today.

"The responsibility sits with them."

Ardern said she was concerned at reports the gunman planned to represent himself in court and could use a trial as a platform for his beliefs.

"I agree that is absolutely something that we need to acknowledge and do what we can to prevent the notoriety that this individual seeks."

"It was clear that one of the gunman's plans was to lift his own profile: "That's something that we can absolutely deny him."