Remote Powerco customers could face another three days before their power is restored.
A bout of foul weather and winds up to 120 km/h tore a strip across the North Island on Saturday, cutting power to about 30,000 customers, ripping rooves off houses and snapping trees like "matchsticks''.
Powerco general manager Andrew McLeod said the company was making good progress, and about 4500 remained without power last night.
"We had 4500 off overnight, we're hopeful of having that down to 2000 around midday today. The last 2000 are going to be hard, it has been a big storm and there's a lot of damage out there,'' he told Radio New Zealand.
He said the remaining customers were in remote or hard to access southern Taranaki and Wanganui locations, and would face another two to three days without power.
"It's very widespread damage, so there's lots of little pockets and lots of individual repairs which will take quite significant work.
We've got about 600 lines down. So it's really all over the place.''
Saturday's weather left a wake of horticultural and severe infrastructure damage in its wake, he said.
"We've got whole sections we will need to rebuild. For example we'll have sections where there may be six or seven polls which need to be replaced, lines re-strung, everything bolted back together. These are big jobs, they need big gear, big cranes, a lot of people out there.
"We were certainly shocked by the scale of destruction really.''
He said 130 field employees worked on Saturday, 170 on Sunday, and close to 200 would be working today. Extra resources from as far as Christchurch and the Coromandel had been brought in to help the repairs.
Water restrictions in Wanganui remain in place after power was cut to the city's pumping stations this weekend.
Wanganui mayor Annette Main said a huge number of people had been working to restore power to the city's bores and residents, after a storm that saw trees fall and snap like "matchsticks''.
She said although power had been restored to all of the bores, it would take some time before the water reservoirs would rise again to the necessary levels.
"It is Monday now, so our industries kick into work this morning, so that means quite a big drain on our water resources,'' she told Radio New Zealand.
"We're asking people to keep abiding by the restrictions we've put in place for the next couple of days, so definitely no washing cars, no watering your gardens, and trying to be really careful with water use in your home.''
She said while the water was discoloured it was still "perfectly safe''.