WELLINGTON - New Zeland's Royal Commission of Inquiry into inner-city building failure during Christchurch's February earthquake should investigate liability, critics said Tuesday.

New Zealand Prime Minister John Key announced on Monday that the inquiry will look in to the "severe" failure of CBD buildings and suggest measure to prevent a repeat.

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Key said the commission would look at two major areas:

-- Buildings in the Christchurch CBD, and why they failed so badly, causing death in the quake. That would include looking in to the characteristics of buildings such as their age, location, and conformity with earthquake risk best practice.

-- It would also look in to the current legal and best-practice requirements for the design, construction and maintenance of buildings in central business districts in New Zealand.

However, Canterbury TV chairman Nick Smith said on Tuesday that an investigation into liability was important.

"I think for anyone in Christchurch...we all want to know the answers. Let's be upfront and say our building standards were not sufficient," he told Radio New Zealand.

Ann Bodkin, who was trapped in the collapsed Pyne Gould Corporation building, also said the commission should find fault.

"There were two buildings that just fell down like a pack of cards and you would really have to ask some questions about their structure."

But lawyer Mai Chen, a public law specialist, said the commission was not a court.

"The purpose of a Royal Commission is to investigate, it's adjudicatory... The purpose of it is to get to the bottom of the matter...not to incriminate," she said.

The commission would examine why Christchurch's buildings collapsed, "so there is quite a lot material in there which could you set you up quite nicely for being prosecuted in other fora after the Royal Commission has reported."

The Royal Commission would report its findings in April 2012, but would release an interim report after six months.

The confirmed death toll in the quake is 172.