Lights out for Earth Hour 

The city of Christchurch and Fiji's capital Suva were the first cities to mark Earth Hour on Saturday night.

The greenhouse awareness initiative was born a year ago in Sydney and has now gone global with 30 countries participating.

Lights were dimmed or turned off in many buildings for an hour at 8pm.

The US cities of San Francisco and Phoenix and Vancouver in Canada will be the final population centres to mark Earth Hour.

Earth Hour is an international campaign to raise awareness of climate change Earth Hour and aims to get residents and businesses to switch off non-essential lights for one hour in a symbolic gesture.

Christchurch is the official New Zealand city involved in Earth Hour, but other cities across the country switched off their lights.

Mayor Bob Parker led the official countdown in Cathedral Square, followed by a public screening of Leonardo DiCaprio's 11th Hour.

Co-organiser Carlin Archer hopes all New Zealanders will get into the spirit of Earth Hour.

He says he is confident it will raise awareness about the environmental effects of climate change.

The campaign has had a big push in Christchurch over the last few weeks, with t-shirts and information in the papers.

Sky City is also doing its bit to save the planet and the outside floodlights of the tower were programmed to turn off at 8pm for Earth Hour.

But authorities are urging householders to take extra care with candles when lights are switched off. Civil Defence spokesman John Fisher says people should make sure they use candles, oil burners, matches and lighters safely.