An eradication programme is under way at Waihi to destroy a foreign newt population that could wipe out endangered native frogs.
In July last year, three European alpine newts, which are a small lizard-like amphibian, were discovered and 300 have since been captured.
It was one of three new organisms discovered in the Western Bay of Plenty since 2012.
The other cases were ants at Mount Maunganui that had been eliminated.
Plants and environment response manager Edwin Massey said it was informed about the European alpine newt in July 2013 when three were found.
During its response, which is ongoing, 300 have been captured within 330m of the original site.
Following surveys, an eradication project was launched.
"We found a number of newts in a small number of water bodies within a 500m area of the original find," Mr Massey said.
"An eradication response is still under way, which involves searching and trapping of all the water bodies and risk areas within the area as typically these newts don't move far from their home.
"This is the first attempt at eradicating a newt in New Zealand."
The European alpine newts were voracious predators and would eat anything they could overpower.
"They feed on a variety of things, including amphibian and fish eggs and larvae, aquatic invertebrates and small vertebrates. The newts are an additional risk to New Zealand's already endangered native frogs."
If the European alpine newt were to establish, it would add a significant threat to the already endangered native Hochstetter's and Archey's frogs.
In 2012, a single incursion of brown crazy ants (Paratrechina longicornis) and Monomorium ants were found at Mount Maunganui.
Both the exotic species had not established in New Zealand and were detected as part of the Ministry for Primary Industries National Invasive Ant Surveillance Programme.
"Exotic ants pose a risk to New Zealand's native fauna and flora, as well as the lifestyle of New Zealanders," Mr Massey said, adding they were eradicated.
In 2012 and 2013, 31 new pests and diseases were identified by MPI.
These included a black widow spider in Taupo, a black rock scorpion in Queenstown and an Australian subterranean termite in Auckland.