Waimakariri District Council says it may be at least a year before services are fully restored following the devastating earthquake.
The council's chief executive, Jim Palmer, says the cost of replacing and repairing damaged public buildings, utilities and roads could top $120 million.
He says the money will come from Government contributions, insurance, and the council, though at this stage it is not known how the costs will be divided between them.
The council is spending $200,000 a day on immediate repairs to infrastructure.
There have been several reports of bogus property assessors approaching householders in Waimakariri District.
Mr Palmer told Morning Report that genuine inspectors carry identification and said if people still have concerns they should talk with the police.
Sewage system damage extensive
On Thursday, the district's mayor, Ron Keating, said waste water services had been restored to 70% of homes in the town of Kaiapoi.
However, he said Saturday's earthquake had damaged parts of the sewage system so badly that some residents may be waiting a year before it can be fully replaced.
The district council is having to pump raw sewage into rivers and waterways because of the damage to pipes and pumping stations.
Tap water had been restored to 90% of users in Kaiapoi, but people should still boil water for three minutes.
In the Waimakariri district towns of Kaiapoi, Pines Beach and Kairaki, a curfew remains in place from 7pm to 7am.
Selwyn considers third welfare centre
The mayor of Selwyn district says consideration is being given to opening a third welfare centre, in Lincoln.
Centres are already open in at Rolleston Community Centre and Darfield Recreation Centre.
Kelvin Coe says more than 300 houses in the district are being assessed and so far 22 have been ruled unsafe.
The area's roads have been repaired and are passable with the exception of two bridges, he says.