Finance ministers and central bank chiefs from the G20 group of rich and developing countries have agreed to adopt common standards on fighting tax evasion, a German government source said on Saturday.
Countries signing up to the new standards, which were developed by the Paris-based Organisation for Economic Cooperation and Development (OECD), agree to exchange tax information to give them a better chance of thwarting evaders.
"This is a breakthrough, a substantial result," the source said. "The aim is to get other countries to follow and adopt these standards."
The source said there had also been agreement on the need to fight terrorist financing, particularly through the monitoring of cash-courier services.
Meanwhile, Finance ministers and central bank chiefs from the world's 20 biggest economies voiced concern on Saturday over sudden currency swings, venturing for the first time into the territory of the more influential Group of Seven.
German Finance Minister Hans Eichel, the meeting's host, said there was a general view that sudden changes in exchange rates or oil prices from global imbalances were undesirable.
He also announced a tentative deal, thrashed out with the US, to write off up to 80 percent of Iraq's $120 billion in foreign debt.
Officials have been at pains to point out that the G20 was not a forum for focussing on exchange rates but the recent sharp falls in the dollar mean it was impossible to discuss the economy without touching on exchange rates.
"The imbalances that exist without doubt in the world economy should not lead to abrupt changes, either in oil prices or exchange rates. That's a common position," Eichel told reporters during a break in the G20 talks that end on Sunday.
The dollar sank to a multi-year low versus the yen and within a whisker of its low against the euro on Friday after remarks from US Federal Reserve Chairman Alan Greenspan.
Policymakers faced a barrage of questions from reporters on exchange rates and European and Japanese delegations, worried the dollar's slide could hurt their exporters, said they were concerned.
Markets are now waiting to see if Sunday's communiqué makes an explicit reference to currencies.
Some G20 members were less bothered and one official said there was no appetite among the G20 as a whole intervene to stem the slide.
But Hiroshi Watanabe, Japan's top financial diplomat, said Tokyo viewed recent forex moves as "very rapid," said it was watching developments closely and added it would take decisive action if necessary.
German Chancellor Gerhard Schroeder, who lunched with ministers, put the blame for the dollar's slide firmly on the huge US budget and current account deficits, a view shared by other delegations.
He said the dollar's exchange rate against the euro was a source of concern and that central banks, including the ECB, should consider what action they could take to halt the dollar's decline.
But Brazilian Finance Minister Antonio Palocci, speaking shortly after Eichel, said "the movement in world currencies is not considered to be a worrying thing" and the ministers' debate had been dominated by the potential impact of oil prices on growth.
"There's concern that oil prices could produce some slowdown in the rhythm of world growth but nothing which would place the process of growth at risk," Palocci told reporters.
Eichel said all regions of the world had homework to do to help the global outlook, which he said was bright despite the fact growth next year was likely to be slightly less than in 2004.
US Treasury Secretary John Snow had committed the US to budgetary consolidation, Eichel said, while Europe and Japan needed to deliver structural reforms to their economies. Asia needed "more flexibility", Eichel said without elaborating.
"There are so many reasons (for the dollar's decline), the twin deficits, the low savings rate," Zhou Xiaochuan, Chinese central bank governor, told reporters. "Alan Greenspan already said that."
Greenspan spooked markets on Friday with a blunt reminder that interest rates were bound to go higher and there was likely to be less demand for US assets.
"It seems persuasive that, given the size of the US current account deficit, a diminished appetite for adding to dollar balances must occur at some point," he said.
The dollar, US equities and Treasury bond prices tumbled after the remarks.
The main focus of Saturday's talks was the global economy, amid concerns a soft patch is appearing in some economies.
Ministers also agreed to apply an Organisation for Economic Co-operation and Development (OECD) code on sharing information on tax matters. Later ministers were due to discuss wider financial stability issues and a proposal on how to restructure debts of countries in crisis - although agreement on this point was not expected after Argentina pulled out of the talks.