Residents of Auckland's eastern suburbs are being warned about the possibility on Thursday of low water pressure or discoloured water.
Power company contractors cut into a water main that supplies drinking water to some Metrowater customers in the St Heliers area.
Engineers from Auckland's bulk water company, Watercare, worked though the night and have repaired the damage, but the area could experience problems while the main is being returned to service.
Metrowater said the water is safe to drink, but people should wait until the water runs clear.
It advised customers to avoid using the discoloured water for washing light-coloured or delicate fabrics.