Kaitaia suffered another lengthy power cut on Tuesday, but this time Top Energy was unable to say what caused it.
The lights went out at 9.07am, from the North Hokianga to the northern side of Whangaroa Harbour, including Kaitaia, Ahipara, Mangamuka, the Aupouri and much of the Karikari peninsulas. A Top Energy generator kept the supply running at Doubtless Bay, including Tokerau.
The outage affected about 10,000 homes and businesses, and put some cellphone sites out of action.
Top Energy used a helicopter and ground crews to inspect the 110kV line between the Kaikohe substation and Kaitaia, but was unable to locate the fault, spokeswoman Philippa White said.
Even after power was restored in Kaitaia at 2.10pm the cause remained unclear.