Secretary of State Alexander M. Haig Jr.'s recent charges about big new arms shipments from Cuba to the leftist guerrillas in El Salvador are an exaggerated picture of the situation, according to U.S. officials familiar with intelligence from Central America.

These officials, who declined to be identified, are in the State Department and the intelligence community. While agreeing that some increase has been detected in the arms flow the past three weeks, they said it was incorrect to describe the traffic as "massive," the term reportedly used by Haig in talking with Republican members of Congress Wednesday.

According to the officials, Haig's comments then and in congressional testimony May 1 apparently were not intended to be deliberately misleading. Instead, they said, he was relying on sketchy reports. And, as one official put it, he "just ran off with it before checking with anyone who had analyzed the material in depth."

The result, the officials added, has been to cause difficulties for administration efforts to explain its El Salvador policy intelligibly to Congress and the American public.

They said Haig's use of what one called "rhetorical overkill that doesn't match the facts" only increases the skepticism of congressional and other critics who charge the administration is straining too hard to justify its contention of heavy Cuban involvement in the Salvadoran civil war.

In his May 1 testimony before a Senate subcommittee, Haig said there was evidence of the arms flow from Cuba increasing again, with the new shipments going by air from Cuba to Honduras and then being trucked into El Salvador.

He described it as an alternate supply route to compensate for the drying up of the flow from Nicaragua, through which the United States contends that massive amounts of communist-supplied weapons poured into El Salvador in late 1980 and early this year.

On Wednesday, Republican members of the House Foreign Affairs Committee quoted Haig as having said in a meeting that "massive shipments" of arms had resumed in the past month. In this instance, the congressman said, Haig told them the arms were coming both from Honduras and Nicaragua.

But officials who dispute Haig's statements give a different account. While conceding that the rebels have received some supplies through Honduras and Guatemala for a long time, they say the flow through these two countries, both controlled by military regimes friendly to Salvadoran authorities, appears to be small and nowhere near the proportions received earlier through Nicaragua.

What attracted Haig's attention, the officials said, were reports received here in late April that Salvadoran army units believed guerrillas in the Guatemala-Honduras border area had more weapons than previously. That touched off speculation in U.S. intelligence circles that they might have been resupplied through Honduras.

But, the officials continued, subsequent analysis of the information gave no grounds for concluding this was the case. Instead, U.S. analysts say, if guerrillas in that area do have new weapons, they probably came from stockpiles set up earlier by the rebels or from a redistribution of arms held by other guerrilla groups.

As to Haig's more recent assertions about Nicaragua, the officials said evidence has been received in the past three weeks indicating that the flow, which administration officials had described as "down to a trickle," had picked up again.

But, the officials cautioned, the information available so far indicates that it is modest compared to the situation earlier this year, and they stressed that it cannot be descirbed as "massive" or even large.