Demolition work is still on hold in the cordoned-off area of Christchurch's central business district.
The area is said to be still very dangerous following the powerful quake aftershocks on Monday.
The Canterbury Earthquake Recovery Authority says 100 buildings now need to be brought down urgently.
Spokesperson Catherine Delore says the authority hopes demolition work can resume some time next week, with the urgent demolition getting priority.
At the moment, she says, only essential personnel are allowed into the red zone.