Sky Tower lights were switched off for Earth Hour. Photo / Michael Craig

World Wildlife Fund say more than half the nation's adults took part in Earth Hour this year, switching off lights and other non-essential appliances.

According to national figures sourced from Transpower, there was a national energy saving of 3.5 per cent while the West Coast saved as much as 8 per cent for the hour.

Estimated savings in other regions included: Northland 1 per cent, Auckland 3 per cent, Waikato 3 per cent, Bay of Plenty nil, Hawke's Bay 3 per cent, Central North Island 7 per cent, Taranaki 5 per cent, Wellington 3 per cent, Nelson-Marlborough 6 per cent, Canterbury 6 per cent, South Canterbury 1 per cent, Otago-Southland 2 per cent.

The effort by 1.5 million people was "an amazing commitment by so many New Zealanders sharing hope for the future and commitment to the planet," said WWF New Zealand executive director Chris Howe.

He said a survey found 51 per cent of New Zealanders older than 18 participated in the March 28 switch-off, which covered 44 cities, towns and districts ranging in population from Auckland to the 800 people on the Chatham Islands.

Hundreds of millions of people in more than 4000 towns and cities around the globe participated.

"Earth Hour showed that Kiwis care about climate change and are taking voluntary action to respond," Mr Howe said.

The survey reported 57 per cent of the people who switched off lights said it inspired them to do something else to reduce their impact on the environment.

A similar Australian survey showed almost half the population participated.

WWF and Earth Hour supporters in Wellington presented the survey results to Environment Minister Nick Smith.

Mr Howe said the results were being released as global talks on climate change started in Bonn this week.

WWF has called for governments around the world to agree to cut global greenhouse gas emissions to 80 per cent of 1990 levels before the year 2050.

It said the target was needed to prevent global temperatures rising more than 2^oC this century.

Even a 2^oC temperature rise is expected to subject up to two billion people to water shortages and threaten extinction for more than 20 per cent of the world's species, according to a 2007 United Nations report.

The New Zealand switch-off was partly driven by some local councils.

However "some didn't take part in this campaign because they didn't feel a symbolic action would make a difference," Mr Howe said.

A recent Government survey showed 53 per cent of citizens said they personally worried about climate change and 87 per cent supported Government incentives for households to improve energy efficiency.

- NZPA