The threat of physical violence is preventing conservation officers from stopping an illegal caribou hunt, Newfoundland and Labrador's Natural Resources Minister Kathy Dunderdale said Monday.

Officials believe at least 40 caribou from the protected Joir River herd have been killed by Quebec Innu hunters, leaving only about 60 animals still alive.

Dunderdale said every time conservation officers try to intervene or make an arrest, the situation becomes dangerous.

"[Officers] did attempt to land over the weekend to lay charges. One helicopter got down but was charged by a Ski-Doo so had to take off again. So it's a very volatile situation," she said.

Dunderdale said when government helicopters get low to the ground the hunters wave bags and ropes as if they are prepared to throw them into the chopper's rotor system and bring it down. She said she has told officers to keep their distance.

"I've given clear instruction that conservation officers are not to put themselves at risk," she said.

There are about 45 armed hunters on snowmobiles along with another 30 people also travelling on snowmobiles in the area. As well, there are more than 100 women and children in the area on the Labrador side of the border, south of Happy Valley-Goose Bay. 

The province believes they are Quebec Innu who say they are exercising a traditional hunt on a caribou herd, but the government says the herd is endangered.

Dunderdale said officers will continue to observe and document the illegal hunt. Once it is over, they will lay charges where there is enough evidence.

The province issued a warning to the Innu last week to stay away from the endangered Joir River caribou herd.