Arab League chief Nabil al-Arabi is fighting an uphill battle to court Russia and China to win their support at the United Nations for the latest Arab plan aimed at ending the bloodshed in Syria.

Russia has made it clear that regime change in Damascus constitutes a "red line," but Arabi said on Sunday as he left for New York that his organisation was in talks with Moscow and Beijing.

He hoped the two veto-wielding countries would change their stand on a draft resolution under discussion at the UN Security Council, based on an Arab proposal for Syrian President Bashar al-Assad to hand over power to his deputy.

The Arab League chief, accompanied by Qatar Prime Minister Sheikh Hamad bin Jassem Al-Thani, is to present details of the plan to the council on Tuesday.

Qatar says the plan foresees the "peaceful departure" of the Syrian regime.

It also calls for an end to the violence and a power transfer, with Assad handing over responsibilities to his deputy, before the launch of negotiations between the government and the opposition.

The Syrian authorities have flatly rejected this formula.

And Moscow, which along with Beijing represents one of Damascus's staunchest allies, remains hostile to the Arab proposition, saying it crosses its clearly drawn lines.

Russian Foreign Minister Sergei Lavrov on Sunday also slammed the Arab League's decision to suspend its hard-won monitoring mission in Syria.

The Arab League suspended its observer mission the previous day saying it took the decision in response to an "upsurge of violence whose victims are innocent civilians."

Russia and China vetoed a previous European-backed draft resolution at the Security Council last October that would have condemned Damascus, accusing the West of seeking regime change.

The League's decision to turn to the Security Council, experts say, aims to step up the pressure on Assad's regime but it is not likely to put a stop to the violence.

"A UN resolution will only put added pressure on the Syrian regime but it is not a solution in itself," said Nevin Mossaad, a political science professor at the University of Cairo.

"There can be no solutions imposed from the outside on Syria, especially because Western powers do not want to intervene militarily in this country," she said.

"The solution will come from the inside but it will take time because the regime is still strong. It has the support of Alawites (a Shiite sect to which Assad belongs) and (minority) Christians who fear what comes after Assad.

"For the moment, there are many people in Syria who still hesitate to let go of the regime, because they fear that they will pay for it dearly, but the regime will eventually weaken and crumble."

An Arab diplomat, familiar with negotiations on the Syria crisis, told AFP that he was convinced that "a lot of blood will still be spilled in Syria before the fall of the regime."

"Even the opposition knows it," he said.

Arabi himself warned of the risks of civil war in Syria.

"The report by the Arab observer mission shows an excessive use of violence by the Syrian security forces, which has led protesters and the opposition to carry weapons, and this could spark a civil war," he said.