The talks were due to begin on Monday but were pushed back due to international disagreement on matters such as who should be invited from the opposition.
The United Nations Special Envoy for Syria, Staffan de Mistura, says "intense disagreements" about who should be involved in indirect peace talks between the Syrian government and opposition groups stopped them starting.
Now he wants discussions underway in Geneva in a matter of days.
"We are going to aim at 'proximity' talks starting on the 29th and ongoing for six months... The first priority will be the focus of the talks of what most Syrians, if not all, want to hear: the possibility of a broad ceasefire, and the possibility of stopping the threat of ISIL."
But there is still no consensus on who will take part.
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"Discussions have been taking place in various capitals, there has been contacts between the (United States) Secretary of State (John) Kerry, the (Russian) Foreign Minister (Sergey) Lavrov, foreign ministers of the region, this is to react to Ankara (Turkey), and they are still ongoing."
Russia has branded some opposition organisations as "terrorists" and says they should be barred from the talks.
Russia wants to include groups such as the Kurds.
Turkey opposes inviting the Kurds.
The main Sunni Arab opposition groups, who are mostly supported by Arab governments and the West, say they will not attend unless they can choose their own delegation.
The Syrian opposition's chief negotiator to the talks, Mohammed Alloush, has told Al Jazeera he's unhappy with the way his delegation has been treated.
"There is pressure on us to give up the natural and legitimate rights of the Syrian people. These pressures are represented in pushing our delegation to head to the talks without any clear agenda, plus giving up the goodwill measures, namely addressing the humanitarian situation which has nothing to do with politics."
Former Syrian army general Asaad al-Zoubi serves under Mr Alloush as head of the opposition's negotiating team.
He hopes Russia, which has been carrying out airstrikes in support of Syrian President Bashar Al-Assad, will change its position.
"We did not expect nor want the Russian position to be like this (supporting Assad). We hope that the Russians will change their position - be moderate or less supportive of the Assad regime. We do not care about the Russian declarations or the Russian position because we know full well that Russian support for the regime will not change."
The last peace conference was held in early 2014.
Since then IS has declared a caliphate across much of Syria and Iraq, and the war has drawn in most world powers.
