Omran al-Zoubi says Saudi Arabia is providing weapons and money to "terrorists," the government's term for rebels fighting to topple President Bashar Assad.
Damascus has previously blamed Sunni Gulf states for its civil war. Al-Zoubi's remarks came after Riyadh said Syria faces a "foreign invasion" by Assad's allies.
His comments were carried by the state-run SANA news agency late Tuesday after Saudi Foreign Minister Prince Saud al-Faisal discussed the conflict with U.S. Secretary of State John Kerry in Jiddah, condemning Assad for bolstering his army with fighters from Lebanon's Iran-backed Hezbollah group.
Saudi Arabia is Washington's key ally and a foe of Iran. It's backing Syria's predominantly Sunni rebels. Tehran supports Assad.