Unison crews have restored power to over 2000 homes and businesses on Tuesday and are "working methodically" to restore the remaining 840 customers.
Unison Relationship Manager, Danny Gough, said the work, post the Napier deluge, was challenging.
"We have made good progress so far, however we are now getting down to the areas which are still affected by flooding, so our task becomes more challenging. The safety of the public and our crews remains paramount and we are working with authorities to ensure safe practice," Gough said.
"Our crews are now working in the worst affected areas and given the level of the floodwaters that may have reached into some homes, they will also complete visual inspections of affected properties' service mains, switchboard and wiring, to ensure we can restore power safely.
"In some instances, these checks can obviously only occur if people are home. If no one appears to be home, and we think there is an issue with the mains supply, we will leave the mains switched off. Customers who return home and find their mains switched off are asked to contact Unison's 24/7 fault line on 0800 2 86476, to ensure it is safe to have power restored to their property.
"We fully understand that people are anxious to get their power restored, so we ask that they continue to bear with us as we go about our task as quickly and as safely as possible. We thank our customers for their ongoing patience and please rest assured our crews will still attend to any emergency situations if required."
