The Chinese devaluation as well as the stock market plunge on growth jitters were all part of a difficult path to a more liberal economy, officials said.  "It's an unbelievably difficult transformation and it's not surprising that there are bumps, that it's not a perfectly smooth process, and I think we had plenty of explanations, opportunity to ask questions, and it was a dialogue, and a very open one," IMF head Christine Lagarde said after the meeting.  But some were less impressed.  "Their explanations weren't very good. They should have been much clearer," said Japanese Finance Minister Taro Aso about the Chinese.  U.S. Treasury Secretary Jack Lew noted that global economies were keen to see the world's second-largest economy move to an exchange rate that reflected market fundamentals.  "When the world has called on China to move toward a more market-determined exchange rate, it's in the context of doing so in an orderly way with clearly articulated policies that can be understood and that reinforce themselves in a positive way," he said in a statement.  G20 officials welcomed strengthening activity in some economies but said that growth fell short of expectations because reforms were not being implemented quickly enough.  Last year, G20 leaders agreed to boost global output over the next five years by 2 percent above what was already expected at the time through coordinated reforms and investment.  Read MoreUK Chancellor: Don't worry, we still love EMs  But they were behind schedule, the G20 communique indicated.  "We are making progress towards our commitments (but)... more effort is needed for implementation," the statement said.  Lagarde was even more explicit, making clear governments had for too long relied on the supply of cheap cash from central banks that have been running ultra-loose monetary policy.  "Monetary policy alone will not cut it. It is necessary. It is recommended from our perspective, particularly in Europe and in Japan still, but it will not cut it on its own," she said.  "Clearly in the fiscal sphere as well as in the structural reforms sphere, more needs to be done, and it needs to accompany and eventually take the baton from the central bank governors."  But, in what appeared to be a vicious circle, the reforms were made more difficult by the weaker global growth, Canadian Finance Minister Joe Oliver told reporters.
The world's top economies have agreed to step up reform to boost global growth, but were split on China's surprise yuan devaluation.