But no ground combat troops would be deployed under the plan, which is to be debated in parliament on Thursday.
Prime Minister Stephen Harper read a motion in the House outlining the mission add-on. With his Conservative majority, the motion is assured of passage.
The original military mission started in November with Canadian war planes joining US-led airstrikes on Islamic State jihadists.
Canada also deployed about 70 special forces troops to train Kurds in northern Iraq.
The opposition has accused Harper of lying when he first outlined parameters of the mission to parliament in October, which were supposed to limit ground forces to a non-combat role.
But the prime minister has been unapologetic -- backed by polling that shows a majority of Canadians support the mission in the aftermath of two attacks in Ottawa and rural Quebec the same month.