Mr Brown said there had been an unprecedented response to the crisis
UK Prime Minister Gordon Brown has said he believes world leaders will "rise to the challenge" of tackling the economic crisis at this week's G20 summit.
Thursday's London meeting would ensure "global solutions" were put in place to help arrest the downturn, he added.
After a Downing Street meeting with Australian prime minister Kevin Rudd, Mr Brown said leaders would do "whatever is necessary".
US President Barack Obama said the G20 must give a "strong message of unity".
Following his meeting with Mr Rudd, Mr Brown said: "The world is coming together and the results of this week will show that global problems... require global solutions.
"I believe the world will rise to the challenge and defeat those who say doing nothing is an option and defeat those who say protectionism is an option."
'Choice to make'
He added: "I think you will find that we are prepared to do whatever is necessary to restore the world economy to the growth it needs and I believe the discussions we are having will show results in that way by the time we get to Thursday.
"We have a choice to make: we can either let the recession run its course and retreat into protectionism and isolationism - a do-nothing approach that will push us further into recession; or we can resolve as a world community to unite, to act and to fight back against the global recession that is hurting people in every country and in every continent.
Progress has been achieved, progress will be achieved in London and further progress will be necessary
Australian prime minister
"This is the test we face and the test we will meet in London this weekend."
Mr Brown said: "We have seen an unprecedented global response to an unprecedented global crisis but there is still more to do over the next few days if we are to forge the new consensus that is necessary to put the world economy on a path back to recovery."
Mr Rudd, who praised Mr Brown as "the driving force in making sure that governments around the world act together", suggested the G20, bring held at the ExCel centre in east London, would be part of a longer process.
"Progress has been achieved, progress will be achieved in London and further progress will be necessary as the year progresses as more data emerges about the challenges in 2010.
"But this, against all historical precedence I have to say, has reflected a strong co-ordinated action and agenda across the participating governments."
On Sunday Chancellor Alistair Darling stressed the G20 summit was part of a "process" and that it was important not to be "overly optimistic" about what could be achieved in a single day.
Mexican President Felipe Calderon has also met Mr Brown, one of a series of world leaders to visit 10 Downing Street in the lead-up to the summit.
Italian Prime Minister Silvio Berlusconi has offered to host an extra G20 meeting in Sardinia at the end of the scheduled July 8 to 10 summit of the G8 group of leading economies.
Mr Brown's spokesman said he saw "merit" in the idea.
Last week, the UK prime minister visited countries including the US, Brazil and Chile, promoting calls for a co-ordinated fiscal stimulus.
In an interview with the Financial Times, US President Barack Obama said: "With respect to the stimulus, there is going to be an accord that G20 countries will do what is necessary to promote trade and growth.
"The most important task for us all is to deliver a strong message of unity in the face of crisis."