Ban spoke Wednesday at The Hague to commemorate the 100th anniversary of the Peace Palace. He said the escalation of the Syrian civil war has resulted in "horrendous casualties."
U.N. inspectors are in Syria investigating chemical weapons claims. Western allies have accused the Syrian government of using illicit weapons, though Syrian allies say it was a rebel move to court international favor.
Hundreds of people were killed last week in a suburb of Damascus in an alleged chemical weapons attack.
Ban said the use of chemical weapons was a violation of international law but stressed it was important to establish the facts. With Western allies examining the possibility of some form of military intervention, Ban said there was still a chance for a peaceful resolution.
"Give peace a chance. Give diplomacy a chance," he said in his remarks Wednesday. "Stop fighting and start talking."
U.N. special envoy to Syria Lakhdar Brahimi said the U.N. Security Council needed to sanction the use of force in Syria. He said it was unclear what form Western military action in Syria would take, but said he didn't see U.S. government as one that was "trigger-happy."
The British government said Wednesday it would present to the Security Council a Chapter VII Resolution authorizing the use of force to protect civilians from chemical weapons.