A senior official from Canada's cyberspy agency says proposed new powers would allow it to stop a terrorist's mobile phone from detonating a car bomb, block the ability of extremists to communicate, or prevent a foreign power from interfering in the country's democratic process.

Shelly Bruce, associate chief of the Communications Security Establishment, told a House of Commons committee Tuesday that a proposed Liberal bill would help the agency counter 'cyberaggression' by foreign states and violent extremism.

A December report by leading Canadian cybersecurity researchers said there is no clear rationale for expanding the CSE's mandate to conduct offensive operations.

It said the scope of the planned authority is not clear — nor does the legislation require that the target of the CSE's intervention pose some kind of meaningful threat to Canada's security interests.

Bruce stressed the proposed legislation contains safeguards that would prohibit the agency from directing active cyberoperations at Canadians.

It would also forbid the CSE from causing death or bodily harm, or wilfully obstructing justice or democracy.