A plan to lift the cordon around part of central Christchurch early Friday morning was called off so the effects of overnight aftershocks could be reassessed, the city's mayor says.
The cordon imposed after Saturday's magnitude-7.1 earthquake was to have been lifted at 5am but police strongly advised against this, saying some buildings were still unstable.
Civil Defence says it intends to relax the cordon as soon as possible but is taking a cautious approach to ensure public safety.
It says although unstable buildings could be individually cordoned off, that would force pedestrians to walk out on the road, putting them in danger.
Christchurch mayor Bob Parker says in light of aftershocks overnight, it was decided to reassess the situation in daylight.
Mr Parker told Morning Report he hoped the cordon would start to be pulled back during the course of today.
Some parts of the city are returning to "something approaching normality", he said, and the mood in the city has lifted.
The boundary of the cordon remains Worcester, St Asaph, Madras and Colombo streets.
In the Waimakariri district towns of Kaiapoi, Pines Beach and Kairaki, a curfew remains in place from 7pm to 7am.