G7 finance chiefs meet on Friday under heavy pressure to take action to revive flagging economic growth in rich nations and calm the biggest confidence crisis in financial markets since the global credit crunch.

Host country France has called for a coordinated response from the Group of Seven industrialized nations after mounting anxiety over Europe's debt crisis and the fragility of its banks caused a big fall in world stock markets in recent weeks.

Differences between the economic problems facing the United States, Britain and euro zone states are complicating the task though, meaning one-size-fits-all solutions will not work.

IMF chief Christine Lagarde said in London before boarding a flight for Marseille that policymakers in advanced economies should use all available tools to boost growth and called for bold action to weather a dangerous new phase of recovery.

She also cautioned against too much fiscal consolidation in a climate of sputtering growth.

But a G7 source told Reuters a unanimous agreement in Marseille on coordinated monetary easing was unlikely.

A source in Brussels has said the G7 would likely agree to keep monetary policy accommodative, slow fiscal consolidation in states where that is possible, and implement structural reforms.

No communique will be issued after the talks, something French Finance Minister Francois Baroin said would make for freer discussions.

In terms of the direction to take between stimulus and budgetary consolidation, some are in favor of a uniform action, Baroin told daily Le Figaro. My tendency is to look for what is most adapted to each country's situation.

G7 finance ministers and central bankers sit down from mid-afternoon in the Mediterranean port city of Marseille.

A working dinner will be followed by briefings from around 9:15 p.m. local time by the French, German, Canadian and Japanese delegations and European Central Bank President Jean-Claude Trichet. The United States plans no briefing.

U.S., OECD WANT STRONG SIGNALS

U.S. Treasury Secretary Timothy Geithner said on Thursday that it was imperative to bolster growth. The OECD called for strong signals from the G7 and urged central banks to keep interest rates low and consider other forms of monetary easing.

With Asian economies deeply concerned about the West's debt crisis and slow growth, Japan said it will voice its concern on the euro zone debt crisis and seek support for its right to unilateral action over safe-haven buying pushing up the yen.

Bank of Japan Governor Masaaki Shirakawa told reporters in Marseille he hoped the talks would share frank views on the crisis and said it was vital that G7 finance chiefs came up with a firm stance to stabilize the world economy.

There are various factors behind the world economy's uncertainty but Europe's debt problem is one major factor. It is important for Europe to tackle its debt problems for its own sake but it would also indirectly bring positive effects on Japan's economy, he said.

Finance Minister Jun Azumi said Japan would ask the G7 for its understanding on its intentions to counter yen rises.

Lagarde said countries must act now, and boldly, giving her blessing to more quantitative easing by central banks and saying the challenge was to find a pace of adjustment that was neither too fast nor too slow.

She said countries facing market pressures must push ahead with urgent fiscal consolidation, while there was scope for slower action in countries not at the mercy of market forces.

If growth continues to lose momentum, balance sheet problems will worsen, fiscal sustainability will be threatened, and the scope for policies to salvage the recovery will disappear, she said.

A Morgan Stanley research note speculated central bankers might soon announce some kind of coordinated monetary easing.

Decisions by the European and British central banks on Thursday to keep interest rates unchanged accentuated the gloom in Europe but neither indicated that a cut was imminent, while Federal Reserve Chairman Ben Bernanke gave no hint of new stimulus to boost the economy in a keenly awaited speech.

Despite speculation about new coordinated forex intervention, a standard final statement remains the most likely outcome, Unicredit said in a research note.

Fears the global economy may be in its most difficult period since the collapse of investment bank Lehman Brothers have added significance to Friday's talks but there has been little evidence of the unity of purpose shown in 2008 and 2009.

U.S. President Barack Obama announced a $447 billion jobs package of tax cuts and spending on Thursday that seeks to jump start the stalled recovery and avert recession.

In debt-ridden Europe, there is little scope for fiscal stimulus, and where there is some wiggle-room -- in Germany and Britain -- there is no political appetite for it.

In a Financial Times opinion piece on Thursday, Geithner said that while a repeat of the massive coordinated fiscal stimulus efforts of 2009 was not possible, decisive action was needed to deal with a bleaker rich world growth outlook.

The Organization for Economic Co-operation and Development says growth across the G7 could slow to an anemic 0.2 percent in the last quarter of 2011. Its chief economist Pier Carlo Padoan urged the G7 to send a clear signal it is ready to take action if growth slows further.

(Additional reporting by Daniel Flynn and John Irish in Paris, Keith Weir in London, David Lawder in Washington and Leika Kihara in Tokyo; Writing by Catherine Bremer, editing by Mike Peacock)