The Liberal Democrat leader Nick Clegg has called on the Government to offer more than rhetoric in its efforts to end the conflict in Darfur.
British officials have been in contact with the Sudanese government and rebel groups to offer the possibility of a summit in London to help bring peace to the troubled region.
At a rally to mark the fifth anniversary of the start of the war, Mr Clegg said the Prime Minister needed to put more pressure on China to use its influence over the Khartoum regime.
"I would not want to denigrate the rhetorical efforts of Gordon Brown, but I am afraid people want to see action rather than more rhetoric, " he said. "He has been extremely reluctant for a long time to say anything controversial to the Chinese, but the fact is the Chinese government, as host of the Olympics has a new responsibility for human rights."
The Sudanese government is heavily dependent on oil sales to China for revenue.
The demonstration, which saw around 3,000 protestors gather outside the Sudanese Embassy in London, was part of a global day of action for Darfur, organised by Amnesty International, Human Rights Watch and the Save Darfur Coalition.
A group of children from the war-torn province, where 200,000 have died and millions more have been displaced, delivered drawings of their experiences of war to Downing Street.
The Prime Minister, who earlier this week met Hollywood actor George Clooney to discuss the crisis, said the impact on young people had been "nothing less than devastating".
"Today, on the fifth Global Day for Darfur, the eyes of the world are rightly focused on the millions of men, woman and children in the region who continue to start each day with the fear of violence, abduction, rape or death," he said.
"The effects on children of the violence in Darfur have been nothing short of devastating: one million children have been forced to flee their homes and now live in crowded camps in need of basic food and water; two million children depend on humanitarian aid to survive; and half of all children are not receiving any education."
