Reporoa caldera is located in North Island

The Reporoa caldera is a 10 km by 15 km caldera in New Zealand's Taupo Volcanic Zone. It formed some 230,000 years ago, in a large eruption that deposited the approximately 100 km Kaingaroa Ignimbrites. It contains three rhyolitic lava domes (Deer Hill, Kairuru and Pukekahu) and the active Reporoa geothermal field. The Waiotapu geothermal area lies just north of the caldera rim, while the Broadlands thermal area lies to the south. The Waikato River runs through the southern half of the caldera.

• http://en.wikipedia.org/wiki/Reporoa Caldera