There's a chance larger, more aggressive blazes may become a fixture for New Zealand firefighters

More than a hundred staff are battling two major bushfires at either end of the country.

With strong winds forecast for Thursday, crews are bolstering containment lines at the big Waiharara wild fire in the Far North.

And in the south, firefighters have contained most of a 280 hectare fire at Wanaka's Emerald Bay.

Peter Dunne from the United Fire Brigades' Association says hotter, drier summers will bring more long-burning fires.

He says Fire and Emergency knows this is a possibility under climate change -- and that it'll put more tension on firefighters.