Water supply during the Northland Field Days is always top of mind for organisers.
A joint Biosecurity New Zealand and Waikato Regional Council work programme is now underway to remove the small cluster of the pest water hyacinth in the river near Huntly.
The agencies are working together with local iwi to ensure any water hyacinth present is located and safely removed. The team will then coordinate ongoing checks to make sure it hasn't come back.
Biosecurity New Zealand's manager of pest management, John Sanson, says water hyacinth is a rapidly growing water weed that if left, can form dense mats that reduce water quality, crowd out native water plants and animals, block irrigation systems and alter ecosystems.
"In this instance, we've found just 2 individual plants in the slow waters at the edges of the river and 1 plant in a cluster of willows further out into the stream.
"The plants have clearly come from a container of water hyacinth being kept at a private property in Huntly backing onto the river. This container was close to a drain next to the river bank and we believe that's how the plants entered the waterway."
Sanson says all known plants have been removed from the water and inspections have found no further sign of the weed.
However, as a precaution, a more comprehensive survey is taking place today, using a boat supplied by the council harbour master.
It is illegal to sell, propagate or distribute water hyacinth. Those who may have seen the pest can call Biosecurity New Zealand’s pests and diseases hotline on 0800 80 99 66.