About 1500 Orion customers remain without power on Monday morning, the result of gale-force winds that battered the South Island last Tuesday.
About 28,000 customers were originally cut off and the company worked through the weekend to restore supply. Most of those still without electricity are in rural communities west of Christchurch.
Chief executive Rob Jamieson said the damage is so extensive that numerous repairs are needed that restore only around 20 customers at a time.
He said this means some customers will remain without power for a few more days.