Anti-mining groups in Northland are planning to block State Highway 1 for two hours today in a protest against an Australian exploration company's plans to begin prospecting for gold and silver.
The protest is due to take place near Puhipuhi at 10am following De Grey Mining's plans to start prospecting north of Whangarei in the next few months.
Allan Halliday, spokesman for Northland iwi Ngati Hau, told Radio New Zealand today that they were concerned over the impact mining would have on the area's waterways.
"The potential damage may well be irreversible."
Mr Halliday said they were legally entitled to block the stretch of highway as it was on Maori customary land.