The CBC report, first aired late on Wednesday, cited briefing notes it said showed the United States turned its Ottawa embassy into a security command post during a six-day spying operation by the top-secret US agency as President Barack Obama and other world leaders met that June.
Reuters has not seen the documents and cannot verify their authenticity.
The CBC report said the operation was no secret to Canadian authorities. It said an NSA briefing note described the operation as "closely co-ordinated with the Canadian partner".
The Canadian equivalent of the NSA is the Communications Security Establishment Canada, or CSEC. Last month Brazil angrily demanded an explanation for media reports which said CSEC agents had targeted its mines and energy industry.
The CBC report said the documents did not reveal the precise targets of the NSA operation, but described part of the US eavesdropping agency's mandate at the Toronto summit as "providing support to policymakers".
A spokesman for Canadian Prime Minister Stephen Harper declined to comment on the allegations in the report, but said security organisations were subject to oversight.
"We do not comment on operational matters related to national security. Our security organisations have independent oversight mechanisms to ensure that they fulfil their mandate in accordance with the law," Jason MacDonald said in an email to Reuters.
CSEC spokeswoman Lauri Sullivan, asked whether the CBC report was accurate, said the agency did not target anyone in Canada through its foreign intelligence activities.
"CSEC cannot ask our international partners to act in a way that circumvents Canadian laws," she added. CSEC, which has a very low public profile, employs about 2,000 people. It is part of the so-called Five Eyes intelligence-sharing network that also includes the United States, Britain, New Zealand and Australia.
CSEC head John Forster had already been scheduled to appear later on Thursday before the House of Commons defence committee to discuss the annual budget for the defense ministry, which has overall responsibility for the agency.
After the allegations that CSEC had spied on Brazil, the British Columbia Civil Liberties Association and the OpenMedia.ca lobby group announced a lawsuit last month alleging such activities were illegal and unconstitutional.
OpenMedia.ca executive director Steve Anderson said Canadians watching the CBC report would "be shocked to discover just how secretive, expensive, and out-of-control our government's spying activities are".
He added in a statement: "This is sure to cause huge damage to Canada's relationships with our other G-20 partners." The US embassy in Ottawa was closed for the Thanksgiving holiday on Thursday.