Scientists say there are signs a once-spectacular geyser at the Whakarewarewa geothermal field in Rotorua is heating up and may be returning to life again.
The Papakura Geyser was known for its continuous hot water eruptions which reached heights of up to three metres. Dormant since 1979, it is showing signs of activity again.
GNS Science staff monitoring pools at the geothermal field say a pool that had been cool for more than 20 years has erupted and is overflowing at 97 degrees.
Increased levels of geothermal fluid in the hot water at Whakarewarewa are showing pressure has increased as water from deep in the earth is pushed toward the surface.
Dozens of bores were closed in the late 1980s to preserve the geysers.
GNS Science vulcanologIist Brad Scott says it shows how long the geyser has taken to recover after 106 bores drilled for commercial and private use were shut down in 1986.
Mr Scott says authorities may now have the balance right between exploiting and protecting the Papakura geyser, but it is time to reconsider whether to further restrict the number of bores.
Following the bore closures geothermal groundwater levels increased, Kuirau Park came back to life, Pohutu Geyser became more active again - but the recovery of other surface features was slower and Papakura, among others, remained dormant.