The Canterbury Earthquake Recovery Authority has made the first of a series of reductions to the central city red zone.
People are warned to pay attention to the changing fence line, in order to keep safe.
The cordon was reduced in the eastern section on Friday afternoon, opening Latimer Square, in the first of several changes expected by the New Year.
Operations general manager Warwick Isaacs says the reduction is complex and needs to be co-ordinated with demolition and repair work.
He says the central city will be far from perfect when people return and infrastructure work will continue for many months.