It is potentially lights out for Aotearoa's largest solar power company, leaving some customers in limbo.

And the government's asking questions about more than $100 million that has already gone from its Green Investment Fund to the company.

SolarZero, which provides solar power systems, with no upfront costs but multi-year leases, has been put in liquidation.

Employees have been advised that due to unsustainable operating losses, and liquidity constraints, the business cannot continue to operate.

User advocacy group Rewiring Aotearoa's chief executive, Mike Casey, said solar remains the future, but the delivery model has moved on.

Casey told Checkpoint the technology itself is "100 percent the future" and was the cheapest energy available to New Zealand households.

Business models "come and go" and it was about getting the most affordable energy in human history to Kiwi households.

Casey said SolarZero "put solar on the map" and accelerated installations in New Zealand, but a changing market and a decrease in prices meant its business model did not have a long-term future.

These days, Casey said it was cheaper for households to own the panels and batteries, financing them on their mortgages rather than leasing them.

But New Zealand was still far behind Australia in the update of solar panels.

Where 35 percent of households in Australia had rooftop solar panels, just 3 percent of Kiwi homes had them.

The average install in New Zealand was about five kilowatts, costing $10,000.

In Australia, the average was 10kW, and about $20,000.

Casey said New Zealand needed to fix the rules and regulations to inherit the "well oiled machine" that was the Australian solar industry.

It was "unfortunate" the customer had lost the option of SolarZero but the right business model "will prevail in this country".