All parties involved in the conflict should halt "all violent acts across the board, launch inclusive political dialogue as soon as possible and discuss reform plans", Beijing's foreign ministry spokesman Hong Leis said.
The diplomatic moves came as Syrian troops advanced on the Baba Amr district of Homs. Dissidents hold the area but have come under three weeks of heavy bombardment from government forces.
A Syrian official said yesterday that Baba Amr would be "cleaned" within hours.
Beijing's intervention seeks to build on influence with the Al Assad regime underpinned by China's opposition to outside involvement in the conflict.
It follows the walkout from an emergency meeting on the crisis on Tuesday by Syria's ambassador to the UN in Geneva, Fayssal Al Hamwi. He accused members of the UN Human Rights Council of promoting terrorism and prolonging the conflict by organising the debate.
The council, which lacks the international legal authority of the UN Security Council, is thought likely this week to condemn human-rights violations by the Al Assad regime.
China is lobbying hard for diplomatic methods of resolving the conflict. Its foreign minister, Yang Jiechi, told the Arab League and senior Saudi Arabian and Algerian ministers in discussions in the past few days of the need for the international community to create conditions favourable for ending the violence, coupled with political initiatives, and the provision of humanitarian aid.
China sided with Russia in vetoing a UN resolution condemning Mr Al Assad's ruthless response to the uprising and outlining plans to end the conflict to an end. Beijing is determined to resist any western intervention to drive Mr Al Assad from power, but wishes to be seen as actively promoting a peaceful resolution of the conflict.
On Tuesday, 13 Syrian rebels were reported killed in an operation to smuggle one of four journalists trapped in Homs, the British photographer Paul Conroy, to safety in Lebanon. The French government said yesterday that two French reporters, Edith Bouvier and William Daniels, remained trapped in Baba Amr. Bouvier and Conroy were injured last week in the attack that killed Marie Colvin, an acclaimed US journalist from The Sunday Times in London, and a French photographer, Remi Ochlik.
The French foreign ministry called on the Syrian authorities to create conditions for the "sure and rapid evacuation" of its nationals, "notably through an immediate ceasefire in Baba Amr".
As civilian casualties continue to grow in the uprising, some of the moral lessons drawn in European capitals have caused dismay.
The loss of life has been played down by the far right, currently contesting the presidential elections in France. And yesterday it prompted a surprising assessment from one of the most sober voices in British journalism, which called the death of rebels while aiding the photographer's rescue "the price of truth".
The Times headlined its editorial comment on the episode: "Smiling and weeping. A journalist is freed but Syrians die. It's the price of truth."
The newspaper said: "The dissidents' sacrifice testified not just to their bravery, but to the importance placed by opponents of the Assad regime on the role of free media in reporting their situation. As one spokesman told The Times, 'The Syrians who died were volunteers who wanted to help the journalists who they knew well and respected for the work they had been doing'.
The Times said responsibility for the deaths of a few western correspondents and many Syrians lay with "those who run and work for the brutal, pig-headed dictatorship of Bashar Al Assad".
Immediate reaction from readers was divided. One wrote: "If war correspondents were to stop putting their lives in danger and citizens were to stop helping them to carry out their mission then the world of despots would become so much more comfortable and the world of their 'subjects' so much more terrifying. These Syrians died in achieving their mission. I think their families will be proud of the sacrifice that they have made to free their country."
But another contributor considered the headline "utterly despicable", and argued that one human life was never worth 13 others and that the journalist, though brave, had freely chosen to operate in dangerous territory.
A Syrian opposition activist, who goes by the name Kinan Ali, said the decisions made by the activists to help get journalists in and out of Syria should be respected.
"To say they sacrificed their lives - it counts for something. It is a big loss. But a bigger loss is the regime making people scared to not cover this accurately and credibly. If those guys didn't do their job, more people would die and no one would know."
Mr Ali said the men who have been smuggling journalists across the border from Lebanon into Syria are also involved in getting medicine and other vital supplies into besieged areas including Baba Amr.
In France, meanwhile, political commentators were weighing the electoral consequences of comments minimising the slaughter in Syria,by Jean-Marie Le Pen, who led the anti-immigration and, critics allege, anti-Islam Front National for 38 years before handing over to his daughter, Marine, last year.
Mr Le Pen said allied forces in the Second World War had more blood on their hands than the Al Assad regime. "Yes, there is shelling every minute, every two minutes," he said on French radio. "But within just 30 seconds in Tokyo, 100,000 civilians were killed. In Nagasaki, Hiroshima, 80,000 were killed. In Dresden, 200,000. The people who carried out these bombings on civilians should keep quiet about Mr Assad and his 6,000 deaths over six months."
He did not find it abnormal that the Syrian state, facing a rebellion "both civil and military", should be defending itself.
Mr Le Pen, 85, recently had a conviction and suspended jail sentence upheld for denial of war crimes by Nazis during the occupation of France.
His daughter was quick to distance herself from his remarks, pointing out on France 2 television that she and not her father was the FN presidential candidate. She added that they were capable of having differences of opinion.
However, after studiously trying to avoid being drawn into comment on Syria, Ms Le Pen said in a live televised debate that the conflict did not involve "only bad guys or good guys". She hoped Mr Al Assad would not be "replaced by Islamist fundamentalists".
* Additional reporting by Zoi Constantine and the Associated Press