Family, friends and colleagues of the 115 people who died in the Canterbury Television building want answers.

They will be a step closer when the biggest single site of tragedy in the February 2011 earthquake is examined at an eight-week Royal Commission hearing starting on Monday.

More than 80 witnesses will be called at the hearing, which will cover the initial building consent issued by the Christchurch City Council, the construction and design, identification of a structural weakness in 1990 and the assessment after the September 4 and Boxing Day quakes in 2010.

Commission executive director Justine Gilliland said the hearing would be "inquisitorial, not adversarial", as the commission's role was not to apportion blame.

The first two weeks of the hearing will focus on witnesses, including the building occupants. They include level- six occupant Nilgun Kulpe, who said the building "dropped like we were in an elevator", and CTV receptionist Mary-Ann Jackson, who told media at the time that she felt the building coming apart as she ran out.

Some family members plan to attend most of the hearing, but for others the prospect is too raw.

Maurice Gardiner, whose sister, Donna Manning, was a CTV personality, said he would attend the hearing where possible. He was unsure if other family members would be present.

"I'm extremely interested to see the outcome - not to apportion blame, but to learn from it," Gardiner said.

"It needs a full, in-depth look at what's happened."

The scope of the hearing was "very good" and he expected mixed emotions during the eight weeks.

"No doubt it will bring up memories and stir up emotions people maybe haven't dealt with from the point of the view of the building and whether something could have been done to save all those people," Gardiner said. "People may be anxious and angry about that. As far the hearing goes, I think it will be a good thing and a healing thing for people as well."

Geoff Brien's wife, Pam, a police administrator, was at a work-related appointment at CTV when the quake struck.

Sitting through the details that led to her death would be "too hard".

"I'll keep an eye on it, but at the end of the day it's going to be a blue duck, isn't it? Nothing's going to happen," Brien said.

A Building and Housing Department report issued in February found the building did not meet the standards of the day.

Brittle columns, intense ground shaking and the asymmetrical layout of shear walls were largely to blame, it found.

The report concluded that concrete in many of the building's columns was significantly weaker than it should have been.

Engineers had previously concluded that the six-storey building, constructed in 1986, had "pancaked", demonstrating major failures in design or construction methods, or both.

The collapse claimed the lives of 28 Japanese students from the Toyama College of Foreign Languages.

A media team from Japan will travel to Christchurch to cover the hearing, while other international news organisations plan to follow it through a live internet feed.

Toyama president Hisao Yoshida said he expected the truth would be "revealed at long last".

"We hope on behalf of our deceased and injured students, and their bereaved families, that every factor which is related with the collapse of the CTV building is made open to the public, and we would like to know why our beloved students [lost] their precious lives," he said.

Former CTV journalist Emily Cooper, who was on a job at Hagley Park when the quake hit, said it would be difficult covering the hearing in her new radio role.

"I covered the inquest and the previous commissions for CTV, and while that was hard, it was still quite fresh. Now, this far down the track, it just brings everything up again and is quite hard to take in."

Cooper wanted to cover the hearing out of "duty" to her 16 workmates who died.

"I know they would do it if they were in my position."

She wanted to know what caused the collapse.

"I worked in that building, I lost my friends in that building and I want answers, not only for myself, but also for the families," she said. "We all had concerns and we want those concerns to be brought up."

Hearings on assessments carried out after the earthquake, and roles and responsibilities, including the training of engineers and organisation of the engineering profession, are scheduled for September.

The commission has until November 12 to complete its work.

- © Fairfax NZ News