The cordon in place around central Christchurch since the earthquake on 22 February is to be reduced on Sunday.
The area has been divided into four green zones and one central red zone by Civil Defence.
National Controller John Hamilton says two green zones - one in the south-west of the city and the other in the south-east - will open for public access from 2pm on Sunday.
The south-west zone is bounded by Rolleston Avenue, Durham Street, Moorhouse Avenue and Armagh Street.
The south-east zone is bounded by Fitzgerald Avenue, Moorhouse Avenue, Barbadoes Street and Oxford Terrace.
Residents and business owners in the zones will be allowed in these areas from 8am, but will need to provide identification and proof of ownership of a property or business.
Information centres will be set up in the areas to help people.
A 30km/h speed restriction in the zones applies.