The Ngapouri-Rotomahana Fault is a seismically and volcanically active area of the central North Island of New Zealand.

Coming from the south the Ngapouri-Rotomahana Fault can be interpreted as a splay of the Paeroa Fault beneath the still geothermally active volcano of Maungaongaonga which defines the most western aspect of the Okataina Volcanic Centre at the eastern margin of the Taupō Rift of the Taupō Volcanic Zone.

Complete rupture of this intra-rift fault occurred just before one major recent volcanic event, being the 1314±12 CE Kaharoa eruption of Mount Tarawera[2] and was associated in time with multiple large hydrothermal eruptions to the south of the Ngapouri Fault that created craters on the southern slopes of Maunga Kākaramea (Rainbow Mountain) and around Lakes Ngāpouri (Opouri) and Tutaeinanga and covered that locality with hydrothermal mud.

Some of the Ngapouri Fault area in turn was covered by about 1 metre (3 ft 3 in) of Rotomahana mud from the western aspects of the 1886 eruption of Mount Tarawera to its north.

[4] On the 14 December 1983 there was a shallow magnitude 5.1 shock, on or close to the Ngapouri fault, near Waiotapu which did a moderate amount of property damage.