The Green Party says its new energy policy could result in 30,000 homes generating solar electricity in its first three years of implementation, but the Government says it could push up power prices.
Under the Greens' new energy policy, the Crown would lend households up to $15,000 at low interest rates to help them install solar power systems.
The Greens want the Crown to lend money to households for the cost of installing photovoltaic systems at the same rate at which it borrows money - at present 4.1 percent.
At current prices, a typical $10,000, three-kilowatt system would produce $1000 worth of electricity a year, the party says, and paying off the debt would cost $900 a year.
Co-leader Russel Norman said the debt would be repaid through rates and be attached to the house rather than the occupants.
Energy Minister Simon Bridges said there was a role for solar power in New Zealand but not if subsidised by the Government and taxpayers.
Bridges said New Zealand already generates 75 per cent of its electricity from renewable sources.