The world's chemical watchdog on Saturday adopted a plan to dismantle Syria's chemical arsenal, shortly before the the UN Security Council votes on a resolution including the blueprint.

"The decision is adopted and it is effective immediately," Organisation for the Prohibition of Chemical Weapons spokesman Michael Luhan told journalists after the Executive Council meeting.

"After a last-moment unexpected delay our Executive Council has met and at 12:38 this morning (2238 GMT) has adopted a decision on an accelerated programme by the OPCW to destroy Syria's chemical weapons," Luhan said.

US Secretary of State John Kerry has called the OPCW document the "rules and regulations" of Syria's chemical disarmament to be enshrined in the UN resolution that is to be voted on at 0000 GMT Saturday.

Luhan said that a there was a "very minor change" to a draft document seen by AFP and "the timetable was not disturbed."

The draft OPCW document said the watchdog will start inspections no later than October 1 and eliminate all of Syria's chemical weapons by mid-2014.

"The decision is effective immediately and we expect an advance team on the ground in Syria by next week," Luhan added.

The chemical weapons deal is the biggest diplomatic achievement on Syria after more than two years of a bitter civil war that the UN says has killed more than 100,000 people.

Syria agreed to give up its chemical weapons as part of a US-Russian deal struck earlier this month.

The 41-member OPCW Executive Council usually takes decisions by consensus, or they require a two-thirds majority vote to pass.

Syria is reported to have around 1,000 metric tons of chemical weapons, including 300 metric tons of sulphur mustard.

In case of non-compliance with the plan, which sees all Syrian chemical weapons and facilities destroyed by mid-2014, the OPCW will discuss the allegation and then take it to the UN Security Council and General Assembly.