A power company warns it will be difficult for smaller retailers to continue operating without changes to the gentailer model.
UK-owned Octopus Energy - which started New Zealand operations in 2022 - has been lobbying the government for change.
Chief operating officer Margaret Cooney said independent retail did "not make financial sense" as the market was dominated by the big gentailers - companies that produced and sold electricity.
She wanted the government to adopt rules similar to the UK and in New Zealand's telecommunications industry.
"[It] basically requires a firm that owns both generation and retail to operate those businesses at arms length and not to cross-subsidise the retail business with the generation business and ensure that the pricing they give the retail business is available to all players in the market," Cooney said.
Cooney said Octopus' approach since launching in New Zealand was not to acquire "lots of mass market customers", but to provide "innovative offerings".
The company just announced a new scheme where new build homeowners could potentially benefit from no power bills.
Octopus Energy and home builder Classic Builders said it was a "simple concept" - no power bills for at least five years, through a combination of a new build home, solar panels, a battery and smart technology.
Cooney said Octopus worked with the builder to determine the best battery and solar panel, modelled the expected power usage, and if households used the expected power, they would not be billed.
"There's solar on the roof, there's a battery, and you'll consume as much of the solar as possible, and then the battery will store some excess and there'll be some of that solar that injects into the grid," she said.
"But by storing that energy into the battery, we can look at those times of the day when it's really expensive to purchase power, and rather than purchasing power for this customer, we're actually exporting it so selling the power on behalf of the customer."
Cooney said Octopus could stack it up financially by acting as the go-between for sending power to the grid.
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