Assad met envoy Alexander Lavrentiev from key ally Russia in Damascus to discuss the negotiations due April 25-26 in Kazakhstan.
Iran and Russia are the major supporters of the Syrian regime and along with rebel backer Turkey have sponsored repeated rounds of talks in the Central Asian nation.
Moscow and Ankara in September inked a buffer zone deal to prevent a massive regime offensive on the Idlib region, near the Turkish border.
Army shelling kills seven in Syria's Idlib: monitor
But the deal has unwound as former Al-Qaeda affiliate Hayat Tahrir al-Sham took full control of the region in January, and the area has come under increasing bombardment.
Assad insisted at the meeting on Friday that "obstacles" blocking the full implementation of the deal be removed, the presidency wrote on Facebook.
He said the main aim of the accord was to "eliminate terrorist groups", as militant fighters have failed to pull out of the specified areas.
The UN has expressed concern over escalating violence in Idlib, warning that the flare-up is threatening aid deliveries to some 2.7 million people in need.
More than 86,500 people fled their homes in February and March as a result of the surge in violence, it said.
Assad has managed to claw back some two thirds of the country since Russia launched a military intervention in 2015, but Idlib remains beyond regime control.
Syria's Al-Watan newspaper reported that Lavrentiev had delivered to Assad a "positive Saudi initiative" after visiting the kingdom, but gave no further details.
Syrian officials made no comment on the report.
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Riyadh has been a key opponent of Assad, but following the regime victories on the battlefield there has been a warming up of relations between Damascus and some of its Arab neighbours.
The Russian foreign ministry said that the meeting with Assad discussed "ensuring long-term political regulation" and "Syria's post-conflict reconstruction and normalisation of Syria's relations with Arab countries".
Syria's war has killed more than 370,000 people and displaced millions since the conflict began with the repression of anti-government protests in 2011.
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