A Vector spokesman said power had been restored to all customers in Auckland this evening, but there could be some "isolated incidents" through the night as the company continued its work.
The company also said hot water usage in parts of Auckland would continue to be monitored to ensure the network did not become overloaded while two cables were still being worked on.
About 2.30pm a statement from Vector said all customers affected by a massive power outage in Auckland had their power restored.
However the statement attracted dozens of emails from angry Ellerslie-based NZ Herald readers who remained powerless, despite Vector's assurances.
Vector spokeswoman Sandy Hodge said from a feeder level, power had been restored, however as two key cables had yet to be brought into service, Vector had been 'back-feeding' the grid and unfortunately Ellerslie had been missed.
"As far as we're concerned from a feeder level - which is not individual houses - what we can see is we've restored everything, but there may still be a pocket there and obviously we're now becoming aware of something in Ellerslie.
"It'll be to do with the reconfiguration of the network and back-feeding it. There's been some pocket that's been missed out so we need to go and see what's happened."
Affected customers were asked to call and log their outage with Vector, Ms Hodge said.
"We're trying to find out where in Ellerslie they are so we can have a closer look at it.
"It wasn't until we put that information out that we became aware that obviously there were some people still out.
"We genuinely thought we had them out. I understand they'd be cross if they thought that we'd forgotten about them."
Ellerslie resident Joe Stowers said he remained without power.
"Vector are trying to tell me it's fixed but I'm sitting in my house and it's not been on....1st world country and 3rd world power infrastructure."
Monique Facon said her parents resided in Ellerslie's Celtic Crescent and were also powerless.
"I have just spoken to them - power is definitely not restored and they have been told that it might be back at 8pm tonight. All houses on both sides of their street are still out."
Meanwhile, an inquiry into the Auckland power outage has been requested by Energy and Resources Minister Simon Bridges.
Mr Bridges said he had today written to the Electricity Authority to request an inquiry.
"This week's outage was a significant event which disrupted thousands of homes and businesses," he said.
"Even in an electricity system that has strong security of supply, which I believe we have, there is always the possibility of something like this happening.
"However, it is important that there is a full inquiry to give the public confidence that risks to power supply are being adequately managed."
The Electricity Authority is an independent Crown entity with wide-ranging powers to gather information and inquire into any matter relating to the electricity industry.
"The Authority will work with all parties involved to carry out a detailed review of the causes of the outage and what actions will need to be taken, or are recommended, to help prevent outages like this in the future," Mr Bridges said.