The delay came as the Syrian Observatory for Human Rights said more than 130,000 people had been killed since the conflict began in March 2011, with the overwhelming majority caused by conventional arms. (Agencies)
The prospects for a peace conference slated for next month appeared to dim further with Syrian media reporting the delivery of invitations to the meeting had been delayed.
Syria had been due to turn over some of the deadliest chemicals in its arsenal to ships by the end of the year, for delivery to a US boat which is to destroy them at sea.
But Norwegian and Danish vessels that had been waiting off the Syrian coast returned to port in Cyprus as it became clear the mission would not go ahead as scheduled.
Lars Hovtun, a spokesman for the Norwegian ship HNoMS Helge Ingstad, gave no new date for the mission to escort the dangerous cargo out of Syria.
"We are still on high alert to go into Syria. We still don't know exactly when the orders will come,” he said.
The international disarmament mission in Syria has acknowledged it is "unlikely" the weapons can be transported to Latakia port in time for the December 31 deadline.
But the Organisation for the Prohibition of Chemical Weapons remained positive, saying the overall plan to rid Syria of its chemical arsenal was on track.
"An enormous amount of work has been accomplished in three months," OPCW spokesman Christian Chartier said.
Chartier said the operation was still on track to meet a deadline to rid Syria of its chemical arsenal by mid-2014.
Nevertheless, the head of the disarmament mission, Sigrid Kaag, called on all parties including Damascus to "intensify efforts" to destroy Syria's chemical arsenal within the timetable.
The delay came as the Syrian Observatory for Human Rights said more than 130,000 people had been killed since the conflict began in March 2011, with the overwhelming majority caused by conventional arms.