Prince Turki Al-Faisal has called for Syrian fighters to be given anti-tank and anti-aircraft weapons to "level the playing field" in their battle against President Bashar Assad.
"What is needed are sophisticated, high-level weapons that can bring down planes, can take out tanks at a distance. This is not getting through," he said, according to Reuters.
"I'm not in government so I don't have to be diplomatic. I assume we're sending weapons and if we were not sending weapons it would be terrible mistake on our part," the prince was quoted as saying at the World Economic Forum in Davos, Switzerland.
"You have to level the playing field. Most of the weapons the fighters have come from captured Syrian stocks and defectors bringing their weapons," he said.
King Abdallah of Jordan, which has taken in some 300,000 Syrian refugees, 20,000 of them in the last week, told the Davos meeting that anyone who thought Assad was going to fall within weeks did not understand the complex situation and the balance of forces.
He called for major powers to craft "a real and inclusive transition plan" for Syria, saying the army must be preserved intact to form the backbone of any new system and avoid the anarchy that prevailed in Iraq after the US-led 2003 invasion.
The UN should stockpile food and emergency supplies in Jordan to be moved into areas of Syria controlled by the opposition to prevent more people leaving. Activists have repeatedly accused Assad of violating international humanitarian laws.