* Yen retreats a touch, still on track for best week in a month
* Euro inches higher, Greek debt deal underlines supportive flows
* Dollar index heads for biggest weekly fall in 9 months
* Aussie down 0.4 percent
LONDON, April 11 (Reuters) - The dollar handed back some minimal gains against the yen on Friday to end a week that has quashed any hint it could be ready to deliver the strength many banks had predicted for this year.
The U.S. currency has lost 2.5 percent against the yen since last Friday, weighed down by guidance from Federal Reserve officials that the U.S. central bank is nowhere near as close to raising base interest rates as markets had begun to believe.
That comes after two weeks of robust gains against the yen, and the clearest signal yet that European policymakers are on the verge of starting to print billions in extra euros, all of which had encouraged many to believe the dollar was ready to break out higher.
In morning trade in Europe, it was down 0.06 percent against the yen and 0.04 percent up against the euro at 101.46 yen and $1.3892 respectively.
"The dollar is looking weak against the yen and sterling, while the euro continues to surprise us," said Lee McDarby, executive director of UK corporate FX sales at Nomura International Plc in London.
"Nothing has fundamentally changed in the US to account for this weakness, but the dollar just can't seem to get any momentum."
The argument at the start of this year was that a recovering U.S. economy and the steady tightening of monetary conditions that would result, while Japan and Europe lag, would see the dollar gain.
Those backing that trade have been shaken out more than once already, however, leaving the market stuck in tight ranges since a burst of activity around an emerging sell-off in January.
"If (ECB President Mario) Draghi starts to take further action with regard to the euro then we may see the dollar begin to finally regain momentum," McDarby said. "But right now it seems investors are unwilling to take too much action."
The dollar index last stood at 79.420, down about 1.2 percent so far this week. If sustained, this will be its biggest weekly fall in nine months.
Underpinning this mix are a range of factors which leave many investors suspicious the global economy is not on a particularly firm footing.
Dealers and strategists point to risks ranging from signals that China and Japan will be very cautious at best with the provision of any further stimulus to their economies, to worries over supplies of Russian gas to Europe and falling consumer prices in several euro zone countries.
That has helped support the view that, now that the financial system is beginning to normalise, prices of growth-related assets like stocks have been inflated too high by the extra cash central banks have provided since 2008.
The Australian dollar, one of the commodity-linked currencies often seen as a proxy for optimism over the global economy, fell almost half a percent overnight as the Nasdaq U.S. tech stocks index saw its biggest daily loss since late 2011.
"The Nikkei has also already been soft this week on the idea that Japan may not after all be set to deliver more stimulus," said Jane Foley, a currency strategist at Rabobank in London.
"When you add in the Chinese central bank saying is would be very cautious in doing anything, then suddenly the market is confronted with the realisation that monetary policy may not be quite as easy or supportive as they had believed." (Editing by John Stonestreet)