Homes and businesses are without power across Northland and the Far North.
Northpower says it has lost a major high voltage line into the substation at Maungatapere, a major feed from the grid, which has caused much of Northland to be without power.
A spokesperson says most of its 65,000 customers are affected, but no specific numbers.
Top Energy was reporting outages from Kaitāia to Cape Reinga on Thursday.
Power and traffic lights are also out in Whangarei, where police have been sent to the city's main intersections to carry out traffic control.
All three of RNZ's transmission sites in Northland are running on back-up generators due to the power outages. The sites are Waipapakauri in the far north, Ohaeawai in the mid-north, and Otaika near Whangarei.
Meanwhile, parts of Northland have been hit by heavy rain overnight, with schools closed and flooding in outlying areas around Kaeo.
While the rain was easing in some places it was lingering in the eastern side of the Far North and surface flooding was expected, Northland Civil Defence said earlier.
RNZ
