UN Secretary-General Ban Ki-moon (Katie Bradford-Crozier)

By Laura Heathcote

Ban Ki-moon has paid tribute to New Zealand's leadership on climate change.

The head of the United Nations has spoken to some 2,000 people at the University of Auckland about global challenges, including climate change and security.

He says climate change is lapping at the feet quite literally in Kiribati and says reducing emissions can't happen without sustainable energy solutions.

"New Zealand is a leader, the vast majority of your energy comes from renewable sources. I thank you for that commitment."

Secretary-General Ban encouraged students to raise awareness of climate change by writing to their elected officials, and by changing their own lifestyles.

He says climate change is lapping at the feet quite literally in Kiribati and elsewhere.

"When I report to the General Assembly later this month, I will call on the international community, world leaders, to make sustainable development as a top priority of our era."