Power has now been restored in Napier after it initially affected about 975 customers, Unison relationship manager Danny Gough said.
The incident occurred just before 3pm and it was believed to be caused by a cable fault in part of the underground network.
Mr Gough said at the time, that they were 'sectionalising' the power, by usuing other parts of the network to supply customers.
By doing so, they had reduced the number of those affected to 569 customers just after 3pm.
The outage was around the Latham St area of Napier.