The meeting at the UN's European headquarters in Geneva was presided over by UN envoy for Syria Staffan de Mistura and representatives of the United States and Russia, who co-chair the group of countries, UN footage showed.
The task force was created earlier this month by the 17-nation International Syria Support Group to help smooth the way towards a planned "cessation of hostilities" between President Bashar al-Assad's regime and non-jihadist rebel forces.
The US and Russian co-chairs have for the past week been involved in intense discussions that helped produce a text of the deal, which has been agreed by the government and the main opposition body.
The fighting should in theory halt at midnight Damascus time (2200 GMT), although the deal allows fighting to continue against the Islamic State group and other jihadists.
More From This Section
The agreement marks the biggest diplomatic push yet to help end Syria's conflict, which has claimed more than 270,000 lives, but it has been plagued by doubts after the failure of previous peace efforts.
Following the task force meeting, de Mistura is set to address the UN Security Council, which is expected to endorse the text.
The UN envoy will then address the media and possibly announce a new round of Syria peace talks, after the latest effort at negotiations were suspended earlier this month amid relentless bombing by regime forces and key Damascus backer Russia.