Several Canadian police forces have adopted new directives which urge officers to avoid firing Tasers at people's chests.

The directive, from Taser International, says police officers should not target a suspect's chest if possible. Instead officers should aim at the back, lower abdomen or the legs.

The manufacturer says the risk of affecting an individual's heart is low from a chest shot, but officers will not be able to determine whether the suspect has been taking drugs or has an underlying heart condition that could cause cardiac arrest.

But the directive is not sitting well with some police officers.

Mike Sutherland is the president of the Winnipeg police association.

"It's going to be a difficult shot and in high-stress, high-volatility type scenarios that's not always going to be possible," he said.

Police forces in Winnipeg, Calgary, and Vancouver, as well as the Royal Canadian Mounted Police, say they will follow the new directive.

The Queensland Police Service (QPS) says it will look into the directive.