Tánaiste and Minister for Foreign Affairs Eamon Gilmore attended the Friends of Syria meeting in Paris.
Foreign ministers and officials from 100 countries met to ensure continued momentum for efforts to pressurise the regime of President Bashar al-Assad.
United Nations chief Ban Ki-moon recommended to the UNSC that its Syria monitoring mission shift focus from observing a non-existent ceasefire to securing a political solution to the conflict that has killed thousands.
Mr Gilmore said: “In responding to the crisis in Syria, we can no longer confine ourselves to mere condemnatory statements and expressions of concern.
“There is a clear need for effective action on the part of the international community to end the violence and to bring the Syrian people's long nightmare to an end.
“An arms embargo is particularly urgent. I support the calls for such a measure voiced here today.
“I welcomed the opportunity to hear directly from representatives of the Syrian opposition today on what more the international community can do."
The 15-member UN council approved in April the deployment of up to 300 unarmed military observers to Syria to oversee a ceasefire that has failed to take hold.
The mission is part of a six-point peace plan proposed by international envoy Kofi Annan.
Mr Ban's report to the council recommends the emphasis of UNSMIS' work shift from military observers.
French President Francois Hollande has called for stiffer sanctions against Mr Assad and more support for rebels seeking to drive him from power.
"Bashar al-Assad must go," Mr Hollande said."It's in the interest of Syria, of its neighbours and everybody who wants peace in the region."
Mr Hollande said he wanted the participants at the talks to also agree to step up humanitarian aid to the country.
Elsewhere, a Syrian general who had been close to President Assad defected to Turkey this week.
Manaf Tlas, who was a brigade commander in Syria's Republican Guard, went to military college with Mr Assad.