Police are investigating the theft of money from an ATM at Winnipeg's Misericordia Health Centre. (Google Street View)

An investigation has been launched into a "large quantity of money" stolen from a banking machine over several years at a Winnipeg hospital, police say.

Winnipeg radio station CJOB reported Monday that upward of $2 million was taken from the machine at the Misericordia Health Centre over a period of 10 years, but police would not say how much cash was stolen, in which hospital the machine was located, or the duration of the crime.

An official at the Misericordia Health Centre, however, confirmed the theft happened there. Heidi Klaschka said police were called in April, immediately after it was determined a theft had occurred.

"There were internal concerns raised, and as soon as they were raised we contracted an external auditing firm and they confirmed a theft," she said.

"At that point we turned that matter over to police."

Police would only say at this stage of the investigation it has been determined that "a large quantity of money was stolen over several years."

Spokesman Const. Jason Michalyshen said it is possible the amount taken could be hundreds of thousands of dollars or even millions.

"This investigation is in its early stages and as a result limited information is available at this time," he said, adding no arrests have been made.

Michalyshen wouldn't speculate about a suspect or suspects, but said it was obviously a person who had some responsibilities for the ATM, and possibly other financial accounts.

Klaschka said new security measures have already been put in place at the hospital.

"The machine was originally run by Misericordia Health Centre, and now it's run by a third-party firm," she said. "That's one of the practices we put into place.

"We also looked at all our financial practices across the board and tightened it up so this will never happen again."