Though progress has been made on restoring electricity and mains water to Christchurch, many residents face weeks without the essential services.
Lines company Orion says electricity has been restored to more than 85% of Christchurch since the earthquake last Tuesday.
Some 27,000 people are still without power, chief executive Roger Sutton said on Wednesday.
Mr Sutton said repair work is ongoing in the the eastern suburbs, and he hopes that at least half of the homes there will have power restored by Sunday.
Others may have to wait weeks before repairs are completed, Mr Sutton has previously said.
Mr Sutton says Orion's biggest problem is a large substation in New Brighton where four large underground cables running into the substation are destroyed.
He says they've built an overhead line to replace them.
Workers are coming up against some obstacles to connecting supply, he says, but the overhead power line replacing underground lines from Bromley to Brighton is finished.
Mr Sutton says staff now face the big job of installing a transformer and switch gear to allow that line to be activated. He expects that will take three to four days.
Water back on for two-thirds of residents
Civil Defence says water is now back on for 70% of Christchurch.
Co-ordinator Steve Brazier says 120 crews are working to restore the supply to the rest of the city.
Christchurch City Council is warning that many households will be waiting much longer than a week to be reconnected to mains supply.
For those still without toilet facilities, 30,000 toilets will begin arriving this week.