Some Northland homes still without power after Cyclone Dovi

Top Energy linemen repair powerlines brought down by a pine tree on Wiroa Rd near Kerikeri. Photo / Peter de Graaf

Winds generated by last weekend's Cyclone Dovi were so fierce power lines supplying half of all Far North households were brought down by falling trees.

About 23,000 homes across Northland lost power on Saturday night, with 17,000 of those in the area covered by Far North lines company Top Energy.

As of 3pm on Monday all but 500 of those had been reconnected with most of those due to have power restored by the end of the day.

North Hokianga was the last major area where the power was still out yesterday afternoon.

Top Energy chief executive Russell Shaw said it could take a few days to restore power to the last 30 or 40 most isolated customers. In one case linemen would have to carry their gear and go in on foot.

Shaw said it was the biggest outage in the 14 years he had been in the job.

He put that down to ''incredible'' wind strength which crews measured at 144km/h — more even than the official 120km/h clocked at Tapeka Pt.

In many cases lines had been taken down by trees on the opposite side of the road blowing over.

''When I went out you couldn't stand up the wind was that strong — and we had line crews out in that. It's a real balance between their safety and making the network safe. If a tree's come down there's a fairly good chance the one next to it will be next.''

Crews were sent home when it got too dangerous, around 10pm on Saturday, and resumed on Sunday morning when the wind had reduced.

By 11pm on Sunday all but 1200 had their power restored, Shaw said.

''It was just a mammoth effort, we had half our customers cut off. I could not be more proud of them. I know it's a huge inconvenience for people but these guys could not have done any more.''

Shaw said the company had tried to keep customers informed over Facebook. Positive comments for the line crews had been collated and filled 90 pages.

''They're now being circulated among staff who were out that night so they know how much they were appreciated by the community.''

Outages covered almost the entire Top Energy network at 8am on Sunday. Image / Top Energy

In the Whangārei and Kaipara districts about 6000 households connected to the Northpower network lost power during the storm.

Of those about 175 — in Tangowahine, Kaiwaka, Brynderwyn, Omana, Tinopai and Parua Bay — still had no power on Sunday night.

The company said it had brought in extra resources and as of Monday afternoon had more than 150 people involved in the repair effort.

However, the volume of jobs and the extent of the damage meant it was likely some customers would still be without power on Monday night and into Tuesday.

Cyclone Dovi's sharp, intense winds had caused extensive damage to poles, overhead lines and transformers, along with the damage caused by trees and branches.

In many cases vegetation had to be cleared before crews could find faults and carry out repairs.

The weekend wasn't just frantic for lines companies.

Many volunteer firefighters didn't see their beds on Saturday night as they raced from one incident to another, most involving downed trees.

Kerikeri Fire Brigade had 16 callouts between 11pm on Saturday and noon on Sunday, including a serious scrub fire sparked by fallen power lines near Panguru on the opposite coast.