In response to a warning from Assad that any Western intervention in Syria would inflame the region, Sheikh Hamad said the risk was if Damascus failed to take "concrete steps" to stop the violence.
"The entire region is at risk of a massive storm," he said after more than three hours of talks between a group of Arab foreign ministers and their Syrian counterpart Walid Muallem.
"What is required of Syria ... is concrete steps that could avoid what happened to other countries," Sheikh Hamad said, in apparent reference to the conflict in Libya and NATO's military intervention.
Assad has warned that any Western intervention in Syria would cause an "earthquake" across the Middle East, Britain's Sunday Telegraph newspaper quoted him as telling one of its journalists.
Sheikh Hamad, however, who chaired the Doha meeting but gave no details on the Arab plan, also said that "leaders must know how to behave, not by delaying and deceiving."
The Syrian delegation will stay on in the Qatari capital to deliver Assad's response, he said, adding that the ministerial team would reconvene on Wednesday in Cairo where the Arab League has its headquarters.
Assad warned of "another Afghanistan" if foreign forces intervened in Syria as they had in Libya, the Sunday Telegraph reported.
Syria is "the fault line, and if you play with the ground you will cause an earthquake -- do you want to see another Afghanistan, or tens of Afghanistans?" he asked.
"Any problem in Syria will burn the whole region. If the plan is to divide Syria, that is to divide the whole region."
During talks in Damascus last Wednesday, the Arab ministers warned Assad to stop the bloodshed and start meaningful reforms or face an international intervention, the Kuwaiti daily Al-Qabas reported.
Citing well-informed Arab sources, the paper said the delegation told Assad that failure to resolve the crisis within the Arab fold would mean "internationalising" the unrest.
"This would mean Syria should expect a foreign intervention and a painful international blockade on the economy and other aspects," the daily said.
China threw its weight behind the Arab mediation effort, with its Middle East envoy Wu Sike saying he had told Assad in Damascus on Thursday that his regime's deadly crackdown on dissent "cannot continue."
Wu said Assad's regime must "respect and respond to the aspirations and rightful demands of the Syrian people," and abandon the crackdown that has killed more than 3,000 people since mid-March, according to UN figures.
Ahead of the Doha encounter, the Syrian foreign ministry accused the Arab ministerial delegation of stoking dissent, having been influenced by "lies spread by television channels."
It said that in Doha, Muallem would inform the delegation of the "true situation in Syria," Syria's official SANA news agency reported.
The Doha talks came as Syrian activists put mounting pressure on the Arab League to suspend Syria's membership of the 22-member bloc.
"Assad's militias have been killing us for eight months. They arrest us and crush us... And you, Arabs, who love rhetoric, what are you doing," the Syrian Revolution 2011, a motor of the dissent, said in a post on its Facebook page.
The activists organised protests across Syria on Sunday calling for the League to "freeze the membership" of Syria.
At least three people were killed in fresh violence, two by snipers and another hit as security forces opened fire in the flashpoint central province of Homs, the Syrian Observatory for Human Rights said.
On Saturday in Homs, 20 Syrian soldiers were killed and 53 wounded in clashes with presumed army deserters, while 10 security agents and a deserter were killed in a bus ambush, the Britain-based watchdog added.