The list of participants to take part in a Syria peace conference next month in Switzerland is not yet finalized, the UN said Thursday.

The list of participants to take part in a Syria peace conference next month in Switzerland is not yet finalized, the UN said Thursday.

UN chief Ban Ki-moon spoke on the subject early Thursday with US Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov, UN spokesman Martin Nesirky said.

"At this point no list has been finalized," he said.

The January 22 peace conference will be held in the lakeside Swiss city of Montreux because of a shortage of hotel rooms in Geneva, which will be hosting a luxury watch fair, a Western diplomat told AFP.

UN-Arab League envoy Lakhdar Brahimi will meet in Geneva on December 20 with Russian and American officials to further prepare for the conference, Nesirky said.

"Ultimately it is the secretary general who will be issuing the invitations," he added.

"It will happen in short order after the December 20 meeting."

According to diplomats, Iran and Saudi Arabia are among more than 30 countries slated to attend the conference, which will last only 24 hours.

"At the moment there are 32 countries invited, but that number may increase because everyone wants to come," an Arab diplomat told AFP.

Most countries will be represented by their top diplomats and "each minister can speak for five minutes," the Arab diplomat said.

The government and the opposition will each send delegations to the meeting, and will hold bilateral talks hosted by Brahimi on January 24 in Geneva.