"There is a real willingness to have convergence at the end of this summit and so I really believe that at the end we'll have a consensus around the two points that sometimes appear as differences: the stimulus of the economy and regulation," he told reporters.

South African President Kgalema Motlanthe urged extra help for developing economies at the summit.

"We are here to put across the position of the developing world, particularly with regards to the need to protect jobs because it's the impact on the real economy which affects ordinary working people ... if we're to find an everlasting solution we must develop a response that is inclusive of working people," he told BBC.

Expectations are high that the leaders of the world's largest economies would be committed to a coordinated response to the economic crisis, an overhaul of the global financial architecture and restraint from protectionism.

Attending the meeting are leaders from Australia, Brazil, Britain, Canada, China, France, Germany, Indonesia, Italy, Japan, the Netherlands, Russia, Saudi Arabia, Spain, South Africa, South Korea, Russia, Turkey, the United States and the European Union (EU).

Top officials from the United Nations, the World Trade Organization, the World Bank, the International Monetary Fund (IMF), New Partnership for Africa's Development (NEPAD), and the Association of Southeast Asian Nations are also joining the gathering.

The leaders will be aiming to enhance coordination of a global fiscal stimulus, reach a consensus on increasing loans to the IMF,and reaffirm commitment to anti-protectionism to help restore global sustainable economic growth and stabilize the financial market.

But the outcome of the summit, however, rests with participants' ability to bridge their differences on economic stimulus plans and reforming the global financial system.

While the White House has pushed for more fiscal measures to help the economy, major European countries, notably Germany and France, remain sceptical about this and they mainly focus on tightening financial regulation and reforming the world financial system to prevent such a crisis in future.

French President Nicolas Sarkozy reportedly has threatened to walk out of the London summit if his demand for stronger financialregulation were not met.

Speaking in an interview with French radio Europe 1 on Wednesday, Sarkozy reiterated that he wouldn't want to "associate" himself with a G20 that would be concluded by "false compromises."