The official confirmed Canada's combat mission on condition of anonymity because the official was not authorised to speak publicly about the plans.
The deployment needs to be voted on in Parliament but Harper's Conservative government has the majority of seats so it is expected to pass.
Canada is among dozens of countries that have signed up to the US led coalition fighting the Islamic State militant group in Iraq and Syria.
Deputy National Security Adviser Ben Rhodes tweeted last month that the US welcomed Harper's announcement that Canada would send military advisers to Iraq as part of the US effort to support Kurdish forces.
More From This Section
Canada also earlier contributed two military cargo planes that carried weapons to Kurdish fighters.
The new combat mission is expected to include a handful of CF-18 fighter jets, refueling tankers and surveillance planes. Further humanitarian assistance is also expected to be announced.
A motion is expected to be debated and voted on Monday. Canada's former Liberal government refused a request to send troops when the US invaded Iraq in 2003, straining ties between the two neighbours. Canada then stepped up its Afghanistan mission.
Harper formally ended Canada's combat role in Afghanistan in 2011. The mission cost 157 soldiers their lives since 2002, shocking Canadians unaccustomed to seeing their troops die in battle.