"Intra-Syrian peace talks will resume in the afternoon of 9 March," de Mistura's office said in a statement.
"The 7th of March 2016 was initially set as the target date for the resumption of peace talks," but a short delay was needed "to allow adequate time to address logistical and practical matters."
"Mr. De Mistura looks forward to Syrian participants' engagement in serious discussions," the statement added.
A first round of talks which began early last month was cut short amid intensifying Russian airstrikes in Syria in support of President Bashar al-Assad's forces.
The UN has said an extended commitment to the ceasefire by all sides would raise hope of the talks succeeding, after repeated diplomatic efforts to end the conflict have failed.
