However, they did not say if the UN team would be allowed to probe allegations that such weapons had been used in the country's civil war.
Ake Sellstrom's full team has not been allowed into Syria due to diplomatic wrangling over access. His mission this week was to prepare the ground for an investigation.
Sellstrom met Foreign Minister Walid al-Moualem, and a joint UN-Syrian statement said "discussions were thorough and productive and led to an agreement on the way forward".
It did not say if the agreement included access for Sellstrom's team.
Damascus has so far refused to let UN investigators go anywhere except Khan al-Assal in Aleppo province, where Syrian President Bashar al-Assad's government and its ally Russia say rebels used chemical weapons in March.
The United States said last month it had proof that the Syrian government had used chemical weapons against fighters trying to overthrow Assad.
UN secretary general Ban Ki-moon has insisted that his team be permitted to visit at least one other location, the city of Homs, site of an alleged chemical attack by government forces in December 2012.
Both sides deny using chemical weapons in a war which the UN says has killed 100 000 people. – Reuters