The long-delayed "Geneva II" peace conference for Syria will open in the Swiss lakeside town of Montreux because of a lack of hotel space in Geneva, the United Nations said Tuesday.

"The international conference on Syria... will be held due to logistical reasons... in Montreux," said Khawal Mattar, spokeswoman for UN-Arab League envoy Lakhdar Brahimi, who is trying to organise the conference.

UN Secretary General Ban Ki-moon finally set a date last month for the talks, which have been repeatedly postponed since June and are now set to kick off on 22 January.