The world's 20 top economies will use all policy tools available to lift sluggish global growth, they said Saturday, despite German disquiet over fiscal and monetary stimulus.

The global recovery was continuing but "remains uneven and falls short of our ambition for strong, sustainable and balanced growth", the G20 finance ministers and central bank chiefs said in a communique in Shanghai.

They met amid fears driven by slowing growth in host nation China, steep falls in world financial markets, and US interest rates having risen for the first time in nine years -- while Japan has adopted negative rates.

The OECD last week cut its 2016 global growth forecast from 3.3 percent to 3.0 percent.

The G20 communique cited a list of specific risks the world faces, including volatile capital flows, falling commodity prices and rising geopolitical tensions, along with "the shock of a potential UK exit from the European Union and a large and increasing number of refugees in some regions".

But disagreements about the right remedy overshadowed the meeting, after Germany's Finance Minister Wolfgang Schaeuble said attempts to boost economies with monetary loosening could be counterproductive and fiscal stimulus -- governments spending more or cutting taxes -- had run its course.

"Fiscal as well as monetary policies have reached their limits," he said. "If you want the real economy to grow there are no shortcuts without reforms."

As the European Union's largest and richest member, Germany sometimes has different economic priorities to other countries and Schaeuble was at odds with the United States, Britain and China, which all backed the use of monetary and fiscal tools to fight a downturn, as well as structural reforms.

US Treasury Secretary Jacob Lew said that weak demand was a key problem, adding: "We need to redouble our efforts to boost global demand rather than relying on the United States as the consumer of first and last resort."

In the event the communique said the group "will use all policy tools - monetary, fiscal and structural - individually and collectively" to build confidence and strengthen the recovery.

But it acknowledged that increasing the money supply alone would not lead to balanced growth and said fiscal policy would be used "flexibly", while giving a nod to the importance of structural reforms.

IMF managing director Christine Lagarde urged: "Without collective, deliberate action on the part of policymakers and implementation there is risk that the recovery could derail."

But analysts were underwhelmed. Lu Zhengwei, chief economist of Citic Bank International, said the language used showed ministers realised the seriousness of the world economic situation, "but the problem... is the implementation".

"The contradictory opinions voiced by Germany means that the consensus among the countries is still not adequate."

- 'Loud and clear' -

While the US Federal Reserve raised interest rates in December, many analysts believe it will delay any more tightening given renewed risks for the US recovery.

This year the Bank of Japan and the European Central Bank (ECB) adopted negative interest rates and huge quantitative easing programmes.

"Every country is trying to stimulate their own economy," said Zhang Jun, director of the China Centre for Economic Research at Fudan University in Shanghai. "The key is not to sacrifice other economies... and avoid a currency war caused by the stimulus."

The G20 meeting was a "platform for communication", he said, but could not restrain any of its members and the communique "won't have a big impact on (the) world economy".

In the communique the group reaffirmed their previous commitment to "refrain from competitive devaluations" and pledged to "consult closely" regarding foreign exchange markets.

There are widespread concerns Beijing could further lower the value of its yuan in order to lift its struggling export sector -- at its competitors' expense -- though Chinese officials have repeatedly denied such plans, including in Shanghai.

Lagarde said that Premier Li Keqiang and all Chinese representatives said "loud and clear" that "there was no intention, no determination, no decision whatsoever to devalue the currency".

Beijing has been on a charm offensive in Shanghai as it seeks to ease concerns over growth in the world's second-largest economy, which has slowed to its weakest in 25 years, including the normally reticent central bank chief Zhou Xiaochuan making two public speeches in one day.

As the world's largest trader in goods China's travails have sent tremors through the global economy and contributed to widespread stock market turmoil, but the ministers did not express any explicit concerns in the communique over their host's situation.

Pierre Moscovici, European Commissioner for Economic and Financial Affairs, said there were no discussions about the country, "not because China was our host, but because China is a major partner".