IMF managing director Christine Lagarde expressed concern about price growth remaining below the target of many central banks, which could hurt the nascent recovery.
If inflation is the genie, then deflation is the ogre that must be fought decisively, Lagarde said at the National Press Club in Washington.
An inflation rate that is well below the 2% targeted by some of the worlds major central banks carries risks in the longer term because it can deflate wages and demand, depressing the economy.
In the US, Federal Reserve officials are stumped about why inflation has stayed so low for so long, and some worry it could be a sign the US recovery is not as strong as some other economic data might indicate.
In theory, inflation should rise as the job market heals.
However, disappointing data on US non-farm payrolls last week offered a cautionary note after a string of data from consumer spending and trade to industrial production had suggested the US economy ended 2013 on strong footing and was positioned to strengthen further this year.
While Decembers unemployment rate fell 0.3 percentage point to 6.7%, its lowest level since October 2008, the decline mostly reflected people leaving the labour force.
Lagarde said central banks should be careful to withdraw monetary stimulus only once the economy is clearly on a firm footing.
Lagarde said the so-called taper of the Feds bond buying was not expected to roil markets as long as it was gradual.
We dont anticipate massive, heavy and serious consequences, she said.
However, she said more rapid adjustments could cause sharp market gyrations and volatile capital flows, which would hit some emerging markets in particular.
Developing economies, which had been the engine of the global recovery after the 2008 financial crisis, are now slowing due to cyclical factors, Lagarde said.
Overall, the direction is positive, but global growth is still too low, too fragile, and too uneven, she said.
US economy expanding at a moderate pace: Fed
The US economy continued to grow at a moderate pace from late November through the end of 2013, with some regions of the country expecting a pick-up in growth, the Federal Reserve said on Wednesday.
In its Beige Book report of anecdotal information on business activity collected from contacts nationwide, the US central bank said two-thirds of the 12 districts reported increases in hiring.
The economic outlook is positive in most districts, with some reports citing expectations for more of the same and some expecting a pick-up in growth, the report said.
The findings were broadly in line with economic data ranging from consumer spending to industrial production that have showed a building up of strength in the economy in late 2013.