Waikato police are investigating an alleged serious assault on the chairman of the region's conservation board on Sunday.
Arthur Hinds, 65, has filed a complaint saying he was punched in the face by an anti-1080 protestor at a public meeting in Tairua, on the Coromandel Peninsula.
Mr Hinds is one of two landowners who are conducting a private aerial 1080-drop.
The police say they were called to the meeting in the town's community centre after reports that a man going into the meeting with his wife was attacked by two men.
They say the victim is alleged to have been knocked to the ground by one man and when he tried to get up, he was prevented from doing so by the second man.
The police say they spoke to one man at the hall and their inquiries are continuing.
A founding member of the conservation organisation Moehau Environment Group, Wayne Todd, says there is never a justification for violence.
He says Mr Hinds is a very environmentally aware man, who helped set up a group to protect kiwi in the Coromandel.
Conservation Minister Kate Wilkinson says the attack was cowardly and atrocious behaviour.
She says the anti-1080 movement on the Coromandel is growing increasingly violent.
Mr Hinds was planning to speak at a the meeting about a proposed marine reserve. He is a proponent of aerial drops of 1080 poison to keep down predators which affect native birds.