Three workers are trapped underground at a western Canadian mine operated by Newmont Corporation, the company and a senior elected official say, adding a rescue operation was underway.

Newmont has temporarily suspended operations at the Red Chris gold and copper mine in British Columbia, the company said in a statement.

David Eby, the premier of British Columbia, said on local television the three had been stranded after an accident overnight.

"They are, to the best of our knowledge, uninjured and in a refuge area," he told a televised press conference.

"Our rescue teams are exceptional, and they will be working overtime to bring these workers home safely to their families."

Newmont has a 70 per cent stake in the mine, with the remaining 30% held by Imperial Metals Corp III.TO.

Imperial Metals confirmed the incident in a statement late on Wednesday.

Newmont reported two "fall of ground" incidents in the accessway to the underground work area of a non-producing part of the mine, a term used to describe when the wall or ground of an underground mine begins to collapse.

Imperial confirmed that the first fall prompted three contractor employees to relocate to a designated refuge station, adding that a second fall subsequently blocked the access route and restricted communication.

"The refuge stations are equipped with adequate food, water, and ventilation to support an extended stay," a Newmont spokesperson said in the statement.

Both companies said that a "stand down of operations" at Red Chris has been implemented and it is assembling specialist teams from nearby mine sites to respond to the situation.

Newmont said it is working to restore communication and safely bring the team members to the surface.