The mayor of Wellington has asked for a review of the council's policy on earthquake strengthening of buildings, a year after it was watered down.
Last year, Wellington City Council doubled the time frame for building owners to comply with the 2006 standards, extending it by up to 20 years in some cases.
Mayor Kerry Prendergast says the relaxed deadlines were to allow owners to budget for the cost of the work, but the Canterbury earthquake has prompted her to ask council officers to review the policy.
"I think in light of what we've seen in Christchurch, not only is there a huge risk to heritage, but most importantly, if it happens during the day, a huge risk of loss of life."
Ms Prendergast says about 600 buildings in the city still require earthquake strengthening.
She says it is possible the council could consider extending financial support for building owners facing big bills for strengthening work.
On Friday, Christchurch City Council brought in a policy requring identified historic and quake-prone buildings to be strengthened to 67% of the building code - twice as strong as the council had originally intended to implement.
City councillor Sue Wells said the policy change affects buildings that have been damaged by a seismic event.
The Historic Places Trust says local councils and the Government must help the owners of heritage buildings bear the cost of earthquake strengthening.
Chief executive Bruce Chapman says while the organisation welcomes moves to introduce higher standards, there is a risk that, faced with huge costs, owners will defer the work as long as possible, putting public safety and the country's heritage at risk.
He says the Historic Places Trust wants to avoid demolition by neglect, where heritage buildings are allowed to fall into disrepair.