Foreign Affairs Minister John Baird is urging China and Russia to lean on the regime of Syrian President Bashar Assad as reports emerge he could unleash chemical weapons on his own people.
The UN Security Council has been powerless to censure Syria because of the objections of veto-wielding Russia and China.
"These reports are deeply disturbing and are absolutely unacceptable," Mr. Baird told the House of Commons on Thursday. "Our government has been very clear that the international community will not tolerate the use of chemical weapons by the Assad regime on the Syrian people.
"We have called on countries like Russia and China to use whatever leverage they have to prevent this serious crisis from entering a new, disastrous phase."
Canada, the U.S. and several European and Arab countries have repeatedly called for Mr. Assad to step down.
Meanwhile, NATO is following through on its plan to place Patriot missiles and troops along Syria's border with Turkey to guard against potential attacks.
The Assad regime denounces this move as psychological warfare and says it won't stop it from defeating the rebel forces it says are terrorists.
"Ultimately Assad and his supporters will be held accountable," Mr. Baird said. "We stand with the Syrian people in their hour of need."
Western countries are wary about arming rebels because of fears of extremists in their ranks.