Friday's Friends of Syria conference will call for an "immediate ceasefire" and access for aid agencies to victims of the weeks of army bombardment, a draft of the final communique seen by dpa states.
The meeting in Tunisia was also set to recognize the opposition Syrian National Council (SNC) as "a legitimate representative of Syrians seeking peaceful democratic change", a step below full recognition.
The draft showed them voicing "strong condemnation of the Syrian regime's ongoing, widespread and systematic human rights violations", particularly the use of heavy artillery and tanks to attack residential areas.
They would also call for the implementation of an Arab League peace plan, under which President Bashar al-Assad would step down - a plan that Russia and China vetoed at the United Nations earlier this month.