Ban said he was preparing proposals for the UN Security Council (UNSC) to act upon in that case because "this would be an abominable crime", Xinhua reported.
"Syria dominated the summit meeting in a way no other political development has ever done at the G20 summit" in St. Petersburg, Russia, last week, he told reporters here at UN headquarters. "It also dominated the bilateral meetings I had with world leaders."
Syrian war has claimed more than 100,000 lives in over two years of war
"The main focus was on the chemical weapons used and the forthcoming report from my investigation team," the secretary- general said. The UN chief, however added that he was yet to receive the probe's report on whether chemical weapons were used in Syria or not.
"But I do know there has been significant speculation regarding use of a chemical agent on Aug 21, leading to the death of hundreds of civilian people," Ban said, referring to an alleged chemical weapons attack in Ghouta area near Syrian capital.
"If it should be confirmed .. then this would be an abominable crime and the international community would certainly have to do something about it."
Should the report from the UN fact-finding team led by Swedish expert Ake Sellstrom confirm the use of chemical weapons, Ban said, "then this would surely be something around which the Security Council could unite in response and indeed something that should merit universal condemnation."
The over two-year old but still ongoing Syrian war has claimed more than 100,000 lives and displaced more than six million people.