A lawyer for the engineering company that designed the CTV building in the 1980s says it is being unfairly blamed for the collapse.
The Royal Commission of Inquiry was called to establish how and why so many buildings collapsed during the Christchurch quakes, as well as the adequacy of building regulations.
Lawyer Hugh Rennie told the inquiry Alan Reay, who owns the company that designed the CTV building, is being blamed for the collapse.
"That right or wrongly was seen as implied accusations and degrees of pre-judgement."
Reay's legal team said it has been forced to do its own investigation, which has found a number of flaws in the CTV Building Collapse Investigation Report's methodology and conclusions.
"There are at least five scenarios that have not been considered as potential collapse scenarios for the building," Reay said.
Reay did not design the building himself, but commissioned an engineer.
Earlier today, Nigel Priestly, a former Professor of Structural Engineering at the University of California, was cross-examined.
Priestly peer-reviewed the Department of Building and Housing report into the collapse. This week, the inquiry has focused on the damning report which found the CTV structure failed to meet three 1986 building standards, and the building collapsed due to three causes.
Released in January 2012, the report, written by Clark Hyland and Ashley Smith, said the building was susceptible to intense horizontal ground shaking, a lack of flexibility in its supporting columns, and the asymmetrical layout of the shear or structural walls made the building twist excessively.
During examination yesterday, Priestly agreed with the report's findings but told the inquiry he had issues with the methods used.
He questioned the method which the consultants used to measure how the building performed in the earthquake, known as Elastic Resistance Spectrum Analysis (ERSA).
"The ERSA was unsuitable for determining the causes and sequence for the CTV building collapse," he said.
He explained it was intended to be used at the design stage to work out how strong to make structural supports in the building, adding: "It's not suitable for determining the expected response when assessing a building."
Priestly said using this method went against the advice from the Society of Earthquake Engineers and he also questioned the formula and equations used by the report's authors.
The professor said the report should have put more weight on the failure of internal columns of the building, as well as the exterior.
At least 80 witnesses are being called during the inquiry, which
covers the initial building consent issued by Christchurch City
Council, the construction and design, identification of a
structural weakness in 1990, and the assessment after Boxing Day
quakes in 2010.