One of Auckland's most celebrated buildings has taken another step towards becoming one of the city's greenest.

Auckland Museum is to fit its roof with large solar panels, generating enough renewable energy to match the power consumption of nine average households. The panels, to be in place by January, continue sustainability efforts by management which earned the museum an award this year for cutting its carbon footprint by nearly a third.

The museum has partnered with Meridian on the panel project, with museum staff reviewing concept designs from potential suppliers.

Expected to generate around 77,000 kWh a year, the system will be one of the largest grid-connected photovoltaic (PV) installations in the country. All solar energy generated will be used onsite, reducing the museum's electricity bill and carbon emissions footprint. The museum still be connected to the national grid.

Museum director Roy Clare said the plan was a "further milestone" in the museum's environmental sustainability programme and aligned with one of his staff's key guiding principles, improved guardianship.

"Environmental practices are changing and more is required of all city buildings," he said.

Carbon-cutting efforts this year saved the museum about $340,000 and made for an annual electricity and gas bill around 35 per cent cheaper than three years ago.

The museum cut its carbon emissions by 365 tonnes last year, or about 21 per cent, bringing the total CO2 reduction in the last two calendar years to 600 tonnes.