Arab League chief Nabil El-Arabi headed to New York on Sunday seeking to win support from the UN Security Council for a plan to end violence in Syria by asking President Bashar Al-Assad to step aside.

El-Arabi will brief the Security Council on Tuesday but the Arab initiative, which is backed by Western states, is facing resistance from Russia and China, two of the five permanent members of the council with veto powers.

El-Arabi, the league's secretary-general, will be joined in New York by Qatari Prime Minister Sheikh Hamad bin Jassim Al-Thani, whose country heads the league's committee charged with following Syrian developments. Qatar and fellow Gulf Arab state Saudi Arabia have been leading efforts to put pressure on Al-Assad.

"We will hold several meetings with representatives from members of the Security Council to obtain the council's support and agreement to the Arab initiative," El-Arabi told reporters in Cairo shortly before leaving for New York.

Asked about China and Russia's reluctance to take new steps over Syria, El-Arabi said he hoped the two nations would change their positions. "There are contacts with China and Russia on this issue," he said.

He also said Arab monitors, whose work was suspended on Saturday after an escalation of violence, had gathered in Damascus and would not leave the Syrian capital until their status was decided following the withdrawal of Gulf observers from the team.

El-Arabi had originally planned to travel on Saturday to brief the Security Council on Monday, but the briefing was put back a day prompting him to delay his departure. He is travelling with senior advisers.

The Arab plan initially included demands for Damascus to pull the military out of residential areas, free political prisoners and start dialogue with the opposition. But Arab ministers, frustrated at the lack of progress, agreed on 22 January to an initiative that called for Al-Assad to step aside.

Some Arab states remain wary of stepping up sanctions or putting other pressure on Syria. Some diplomats say some Arab states are also concerned that approaching the Security Council takes the issue out of Arab hands.

El-Arabi said Algeria had voiced reservations about the part of the league resolution related to informing the Security Council.

A diplomatic source from another Arab state told Reuters, regarding any move by the Security Council to impose sanctions: "If we review such cases in Iraq and other places, I think that kind of punishment didn't yield a lot."

Arab states have imposed economic sanctions on Syria's government, but diplomats say they have limited impact because neighbouring states such as Iraq and Lebanon did not implement them.