A geyser which has been dormant for more than 35 years has caught locals off guard after suddenly erupting.
The Papakura Geyser is located at the Te Puia Te Whakarewarewa Thermal Valley in Rotorua, where there are more than 500 geothermal wonders.
This particular geyser had not shown any signs of strong life since 1979 - until last week, when intermittent "bubbling'' reached boiling point.
Staff at Te Puia reported that the geyser erupted continuously for about 36 hours and shot water up to 4m high.
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Te Puia's chief executive, Tim Cossar, said: "We keep a close eye on our various geothermal features to monitor any changes, and to see her suddenly start erupting was extremely exciting.
"We don't know when she will start again or how long she will continue to perform for us, but it was certainly fantastic to see it.''
GNS Volcano Information Specialist, Brad Scott, said the Papakura geyser was entering a new phase of recovery and experts would be monitoring its progress over the next few months.
"Over the past 18 months she has obviously pumped out the cold water and started hitting temperatures that allow for an eruption. We will be collecting water samples to confirm any changes in the water to support these observations,'' he said.
"It is early days in our scientific investigation of these developments, but the geyser has clearly entered phase two of its recovery. In the first phase, which started 18 months ago, she attained a level of overflow and started regaining some heat, but it was not hot enough to prompt an eruption.