Staffan de Mistura told the pan-Arab newspaper Al-Hayat it was his “intention” for the talks aimed at ending Syria’s five-year war to begin in the afternoon of March 9.
The new round of indirect negotiations between the Damascus regime and the opposition will be the first since a truce between government forces and rebels began more than a week ago.
France, Britain and Germany called on the opposition to attend the talks, but warned that the negotiations would succeed only if humanitarian access were granted and the truce respected.
“In my opinion we will start on the 10th of the month. That is when the process will start”, he said according to an Arabic translation of his remarks published by the newspaper.
Mr de Mistura said he plans to invite members of the government, the opposition, civil society and women to the peace talks.
A spokeswoman for British Prime Minister David Cameron said the European leaders told Putin the truce must be used to try to secure peace without Assad, but their main point on the phone call was to welcome the fact the truce appeared to be holding.
As rockets fired by government forces were reported to hit near the rebel-held town of Jisr al-Shughour in Idlib province, an influential rebel group said there could be no ceasefire while attacks continue.
The agreement is the first of its kind during a conflict that has killed more than 250,000 people and created refugee crises in the Middle East and Europe.
The envoy said on Friday that the Syrian people, not foreigners, should decide Assad’s fate.
The Syrian opposition appears at odds with its Western backers over the success of the truce.
Saudi Foreign Minister Adel al-Jubeir, whose country backs the rebels, said on Saturday that Syrian President Bashar al-Assad must leave at the beginning of a political transition, not at the end.
A regime advance supported by Russian warplanes inflicted serious setbacks on the rebels and weakened the opposition’s position in negotiations.
The latest round, more than a month after de Mistura suspended the previous sit-down, comes as Russian Federation and the United States reached an agreement on a ceasefire that took effect on February 27 and has been observed for the most part since then.
Jubeir said Syria’s opposition “can’t go into talks empty-handed”. Opposition coordinator Riad Hijab said the conditions for talks were “not favourable” but it was too early to say whether they would happen or not.
The opposition has demanded the release of prisoners and the delivery of humanitarian aid according to UN Security Council resolution 2254.
The fall-off in violence has made aid deliveries easier in some areas of the country, but de Mistura said the Syrian government should be processing aid faster.
“The regime is moving forces from place to place, preparing for operations”, said the commander, whose group has also committed to the cessation of hostilities agreement.
On Saturday, the day after water returned to pumping stations in Aleppo after a three-month shortage, electricity also slowly returned to Syria’s former economic powerhouse.
While Islamist groups like Jaish al-Islam and Jaish al-Fatah are part of the group of opposition entities permitted to negotiate over Syria’s future the al-Qaeda affiliated Jabhat al-Nusra and the Islamic State are not and are excluded from the current ceasefire.