Business inventories rose sharply in March, the government reported yesterday, but analysts said the jump was smaller than expected and did not raise new fears of serious imbalances in the economy.

Commerce Department figures showed inventory levels up 1.3 percent in March following an 0.9 percent rise in February, leaving stocks at a new level of $392.3 billion, up from $387.41 billion before.

Although the increase was a substantial one, sales levels surged even more sharply, pushing the closely watched inventory-to-sales ratio down to 1.37 months' supply, from 1.41 months' worth in February.

Sales levels soared 3.8 perecent in March, bloated by a bounceback from the impact of adverse weather in Februaryy and by anticipatory buying in advance of the Teamsters' strike. The rise is expected to be lower in April.

Economists had feared that continued sharp increased in stockbuilding could leave wholesalers and retailers with an excess in inventories, leading to an abrupt slump in output if consumer buying fell off later in the year.

However. Commerce Department analysts said yesterday the rise was not sharp enough to raise these fears again. William Cox, the agency's deputy chief economist, said the boost was less than figured for preliminary GNP estimates.