Three suspected illegal timber mills in the South Island have been raided.
Ten cubic metres of indigenous timber suspected to have been illegally milled was found near Takaka in Golden Bay after search warrants were executed at the sites last week.
The Ministry for Primary Industries says charges may follow once its investigations are complete.
The harvesting of privately-owned indigenous forests is permitted, provided the sawmills are registered and have the correct approval.
The ministry says regulations are in place to ensure the milling of native forests is done in a sustainable way.
Its southern regional compliance manager, John Slaughter, says illegal milling is a major threat to New Zealand's indigenous forests.