Northland's extensive power cut could cost the region $60 million by the end of Saturday, economics consultants Infometrics says.
It is a slightly more conservative estimate than the Northland Chamber of Commerce, which has put losses at about $80m.
Power went out across the region from late-morning on Thursday after a power pylon fell over.
Nearly 100,000 properties were affected.
Most had their supply restored by the end of Thursday but blackouts were expected to continue through Friday and consumers were warned to try to reduce their use.
Infometrics chief executive Brad Olsen said the $60m estimate came from analysis of public estimates of the economic cost of the 1998 Auckland blackout, adjusted for inflation, economic differences between Auckland and Northland between 1998 and 2024, and other factors.
"We have also assumed that most businesses were restricted from operating on Thursday, with 30 percent of businesses restricted on Friday and 30 percent of Saturday's activity curtailed too.
"It's hard to get a gauge of the scale of disruption at present, but this high-level figure provides a guide for the scale of difficulties faced in Northland."
It comes as the region prepares for its main route into Auckland, via State Highway One, to reopen next week, after many months of closure that also affected many businesses.
Olsen said it was concerning that an entire region could be cut off from the rest of the country so readily.
"As Northland has been in recent years. Both the closure of SH1 through the Brynderwyn Hill and now power being cut to the north ... resilience is critical to ensuring the economy is able to function and that businesses can operate without constantly worrying about being disconnected physically and virtually."
Anna Vu Beauty Spa owner Anna Vu said having to close her doors on Thursday - usually the busiest day of the week - could have cost her $3000 or $4000 in lost business.
It was what should have been a late night for many hairdressers, too, who had to push their clients out to future dates.
Hair by ME owner Megan Edwards said the repercussions of the power cut would be felt by her business for weeks to come.
RNZ
