The power company Orion hopes to have electricity restored to all households in Christchurch by the end of Monday.
Orion chief executive Roger Sutton says the company has been working non-stop for 11 days to get the power back on, and its goal is to have 99% of customers restored to the grid by the end of Monday.
About 13,000 people are still without power, 8000 of them in the eastern suburbs, where Mr Sutton says the company is facing complex problems.
About eight cables were damaged in that area, he says, with some of them having four or five faults.
He says that's about eight times the number of faults the company would normally have to cope with in an entire year.
In the meantime, Orion is reminding residents in the eastern suburbs of the need to conserve power in order to avoid overloading the under-strength network.
Mr Sutton says much of the eastern area is being supplied using diesel generators or smaller than normal cables.
Some 4,400 customers have been connected to 21 generators in the eastern suburbs.
Mr Sutton says there have already been power cuts, and people need to conserve electricity so there is enough to go around.