The UN special envoy to Syria, Staffan de Mistura, expects “substantive, deeper” talks between the government and opposition to begin on Monday.
Mr de Mistura said the agenda would include the formation of a transitional administration and elections.
But it is not clear who will attend the indirect talks in Geneva, with some opposition leaders yet to confirm.
On the ground in Syria, a partial truce that began 12 days ago has considerably reduced the intensity of the fighting.
Mr de Mistura said the cessation of hostilities was holding “by and large” and was open-ended as far as the UN was concerned.
The first round of talks on a political solution to the conflict in Syria was suspended last month while still in the “preparatory” phase, with both sides blaming each other.
It came as government forces, backed by Russian air strikes, launched a major offensive on opposition-controlled areas around the northern city of Aleppo.
The government succeeded in cutting a key rebel supply route from Turkey to Aleppo before the US and Russia brokered the cessation of hostilities agreement, which does not include the jihadist groups Islamic State (IS) and al-Nusra Front.
At a news conference in Geneva on Wednesday, Mr de Mistura welcomed what he described as “a sustained reduction of violence”.
“Incidents are taking place, no question and they are. I’m expecting even worse incidents to take place, probably caused by spoilers,” he added.
“The secret will be whether the sides are in a position, as so far touch wood has been the case, [to] contain them, make them not become an unravelling of what has been after five years quite a change… for the life of every Syrian.”
Mr de Mistura said he expected informal discussions to begin at hotels across Geneva immediately, but that formal talks would not resume until Monday.
He added that they would once again be indirect “proximity” talks, with representatives of the warring parties located in separate rooms, and would last only 10 days before pausing for a week.
“We believe that having a timetable and a time limit is healthy for everyone so that we don’t think that we can go on… for two weeks hoping to get into substance – we go seriously into substance as soon as we can.”
The BBC’s Imogen Foulkes in Geneva says the focus of the talks will be a transitional government, a new constitution, and elections. Humanitarian access and ceasefire violations will not be on the agenda.
The UN has set up two taskforces to deal with those issues, and clearly wants the opposition and government representatives to concentrate on a political settlement, our correspondent adds.
UN aid agencies say good progress has been made getting supplies to besieged areas, with almost 240,000 people reached, most of whom received nothing in the last year.
But our correspondent says it remains unclear exactly who will arrive in Geneva on Monday, with some opposition leaders suggesting they have not yet decided whether to attend.
Meanwhile, UN High Commissioner for Human Rights Zeid Raad Al Hussein told the BBC that the international system had failed Syria.
“We’ve seen in this conflict… almost every conceivable war crime allegedly being committed, in addition to crimes against humanity,” he said.
“What does it say to us? It says… that the international system is incapable of addressing this sort of conflict. So future ‘Syrias’ – we have no algorithm, no formula, for how we address these conflicts. And it doesn’t bode well for the 21st Century, of course,” he added.