OTTAWA–Canadian police agencies' use of cutting-edge facial recognition technology presents "enormous" potential for abuse, the opposition New Democrats say.

The NDP is calling on federal privacy commissioner Daniel Therrien to launch a probe into how the RCMP and other Canadian law enforcement agencies use the controversial tool, which can allow police to quickly check citizens' faces against databases of mug shots or social media profiles.

"The power of this technology to radically alter the basic notions of privacy is evident … The potential for abuse is enormous," NDP ethics critic Charlie Angus wrote in a letter to Therrien that was obtained by the Star.

"Any use of such technology must be carried out under clear judicial oversight. However, this technology is being tested and implemented in a legislative and judicial background."

Numerous police agencies, including the Toronto Police Service, have facial recognition programs already up and running, but there's been little public debate about acceptable uses for the powerful technology.

In a report last year, Toronto police Chief Mark Saunders said the force only uses facial recognition technology in criminal investigations, and sharply limits the number of officers with access to the database. Only lawfully obtained mug shots are included in the database, Saunders said.

However, police forces in other jurisdictions are less restrictive in their use of the technology.

The New York Times recently reported on a U.S. company called Clearview AI, which offers facial recognition databases to law enforcement agencies, the contents of which have been scraped from social media profiles.

It's not clear if any Canadian agency has purchased Clearview AI's services, but Angus said it's "imperative" Canadians understand more about how this type of technology can be used.

Alex Boutilier is an Ottawa-based reporter covering national politics. Follow him on Twitter: @alexboutilier