The top Canadian officer at the North American Aerospace Defence Command says the system needs to evolve to meet modern threats.
Speaking at the Banff Global Business Forum on Thursday, Lt.-Gen. Pierre St-Amand says North America is less secure than it was a short time ago as long-range cruise missiles and the actions of some nations create new threats for the continent.
He says the time has come to evolve for the future as NORAD approaches its 60th anniversary.
St-Amand's comments come a week after he told the House of Commons defence committee looking into North Korean threats that U.S. policy is not to defend Canada with its missile defence system.
He says in Banff, however, that NORAD's initial premise of mutual defence between Canada and the U.S. is still very much valued today.
Prime Minister Justin Trudeau said on Tuesday that the government has not changed its position of not participating in the missile defence system, but continues to evaluate options.