British Prime Minister Gordon Brown stressed the need for the leaders to find agreement at Thursday's summit, which is being held amid mounting dissatisfaction about the role of private banks, City financial institutions and individuals in creating the current global financial crisis.
Prime Minister Manmohan Singh is expected to arrive Tuesday night GMT.
Brown warned of tough negotiations ahead, saying, "I have got to do a lot of work in the next two days, getting countries to agree to proposals that we have been working on for some time."
"We are hopeful of getting a conclusion but a lot of great work has got to be done," he told reporters after meeting Mexican President Felipe Calderon in London Monday.
With anti-capitalist demonstrations planned throughout their stay - and fears of anarchist violence - visiting world leaders have been blanketed in unprecedented security.
Some 84,000 police man-hours have been allocated to Operation Glencoe, the G20 security strategy. All police leave has been cancelled in London for Wednesday and Thursday.
Police will throw a 'ring of steel' around the summit venue - the river-front ExCel Centre in East London - as part of a security that is costing the British taxpayer 7.5 million pounds.
Brown said the summit came at "a decisive moment for the world economy" and called for "proper resourcing" of international financial institutions like the World Bank and IMF to enable them to help return emerging market economies to stronger growth.
He said the G20 nations also had to do "whatever is necessary" to bring about the resumption of growth, resist protectionism, boost trade and deliver a low-carbon and sustainable recovery for the future.
The G20 countries are: Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, Britain, the US and the EU.
copyright 2009 by IANS.