The Royal Commission on the Canterbury earthquakes has heard about how earthquake-strengthened older buildings withstand tremors.
The third phase of the commission's hearings has been focussing on the performance of unreinforced stone and brick buildings in the earthquakes.
The commission heard on Tuesday from Californian engineer Bret Lizundia who has carried out a peer review of a report on the unreinforced masonry buildings.
The report by Auckland University engineering professor Jason Ingham was presented to the commission on Monday.
The hearing was disrupted for more than an hour on Tuesday morning when the teleconference line went down.
When communications were restored, Mr Lizundia told the commission he had been concerned that Christchurch had been hit by another earthquake.
Mr Lizundia told the commission he believes the ability for retrofitted older buildings to withstand a severe earthquake had been overstated in the earlier report.
He said while the buildings perform better than unstrengthened buildings, in some cases they still suffer significant damage.
He also urged the Commission to act now in introducing tougher rules for buildings while the disaster is fresh in people's minds and there is public and political backing for change.
He said he hopes New Zealand realises the current passive system is not adequate in a earthquake-prone country.
Another engineer, Fred Turner, told the Commission it should not be assumed that the only options for the older style brick and stone buildings are expensive strengthening or to do nothing.
He said sometimes the best option is to demolish them.