The Electricity Authority is proposing changes to how power costs are determined, which could hit the pockets of thousands of Kiwi homes and businesses.
The changes would introduce a location-based pricing scheme, dropping prices in Southland and Otago but raising them in upper North Island.
Regions that have had grid upgrades would pay more, while those needing more investment would need to pay less.
But a handful of businesses and Government groups are asking for a judicial review into the proposal.
Employers and Manufacturers Association chief executive Kim Campbell says the scheme is being rushed through under the radar.
"To suddenly decide we're actually going to change that without actually having a transitional arrangement or letting people know it's going to happen is actually outrageous. It's a national scandal."
He says the proposed pricing plan will determine prices based on location, rather than use.
"A medium-sized business in Auckland will be paying between $3000 and $7000 a year more for their power. Households could be up to $200 more. Bigger users, it could be in the millions. The further north you go, the more difficult it gets."
Mr Campbell says if it goes ahead, there will not just be increases in power bills - but job losses.
The changes are opposed by Ashburton District Council, Auckland Chamber of Commerce, Counties Power, Counties Power Consumer Trust, EA Networks, EMA, Entrust, Auckland Federated Farmers, Northpower, Norske Skog, Top Energy, Vector and the Green Party.
Electricity Authority chief executive Carl Hansen says everyone will save money over time, as the new pricing model will lead to more efficient investment in the national grid.