The lines company Orion says it may take about a week to fix a major power cable, the damage to which is affecting power supply in southern parts of Christchurch.
Chief executive Roger Sutton says the cable was damaged and leaked oil after being hit by a water supply contractor on Thursday.
He says contractors are chipping away at the concrete encasing the damaged line so they can get to it and repair it.
In the meantime, people in St Martins, Spreydon, the Port Hills and Cashmere need to conserve power to avoid further cuts.
About 6000 customers in Christchurch remain without electricity as a result of the 22 February earthquake.
