After living 41 years as best friends, two Canadians have wept as they confirmed they were switched at birth.

Recent DNA tests showed that one man was raised by the biological mother of the other, and the news was confirmed by Manitoba indigenous politician Eric Robinson, the province's former minister of indigenous affairs.

"What happened here is lives were stolen," he said.

"You can't describe it as anything less than that."

The mistake is the second case of the government-managed Norway House Indian hospital exchanging babies at birth. in a village of some 5000 residents located more than 450km north of Winnipeg by air.

Leon Swanson was born on January 31, 1975, at the Norway House, and David Tait Jr was born at the same facility three days later.

"I want answers, I want answers," Mr Tait said through tears.

"We don't have words. Forty years gone ... just distraught, confused, angry."

Genetic tests confirmed that Mr Tait was the biological child of Charlotte Mason, the woman who had raised Mr Swanson.

Mr Swanson is still waiting for his test results, but the families said they are sure of the swap.

In a similar case last November, Luke Monias and Norman Barkman from Garden Hill First Nation - both born five months before Mr Swanson and Mr Tait - also learned from DNA testing that they were switched at birth.

That case prompted Mr Swanson, Mr Tait and their families to seek out genetic testing based on suspicions that the men might have been swapped because of traits shared with the opposite parents.

"I can't describe this matter as anything less than criminal," Mr Robinson said.

"We can live with one mistake, but two mistakes of a similar nature is not acceptable."

Canadian federal health minister Jane Philpott said in a statement that a third-party investigation would examine the case.

"Cases like this are an unfortunate reminder to Canadians of how urgent the need is to provide all indigenous people with high-quality health care," Ms Philpott said.

She also offered DNA testing to those people born at the hospital in the 70s.