The Christchurch City Council says more consultation is needed on the two designs proposed for stopping flooding in the Flockton Basin before a final decision is made.
The chosen design will be used to protect properties in the Dudley Creek catchment that have been flooded numerous times since the earthquakes of 2010-11.
Option one is a bypass channel that goes along Banks Avenue and through the residential red zone, while option two is a bypass through Marian College and Richmond Park.
Today, the council contracted Beca Consultancy Services to assess the options and do further community consultation.
The council's manager of infrastructure, John Mackie, said it was vital the options were explored in depth, so residents and elected members could remain fully informed.
Mr Mackie said there had been delays with the decision making process, but the right decision needed to be made to ensure the maximum benefit to the community.
The consultation report is to be presented to the council in July, with a target date for completion of the project set for winter 2017.