A group of influential Salvadoran businessmen, reacting to U.S. complaints about human-rights abuses, today accused U.S. Ambassador Deane R. Hinton of acting like a Roman proconsul, violating Salvadoran sovereignty "and the dignity of the Salvadoran people."

The strongly worded charges came in a full-page paid advertisement by the Chamber of Commerce and Industry of El Salvador in one of the country's two main morning newspapers. It marked the first public response from El Salvador's powerful right wing to Hinton's speech Friday in which he warned that U.S. aid might be cut off unless Salvadoran authorities crack down on human-rights violations.

Charging that Hinton's warning constituted meddling in El Salvador's internal affairs, the businessmen described it as an "act of arrogant imperiousness, contrary to ethics and law, that cannot be tolerated no matter whom it comes from.

"It wounded in their deepest roots the feelings of the Salvadoran people, which does not admit or tolerate these 'proconsular' attitudes adopted not long ago by his predecessor, Mr. Robert White, appropriate for a delegate of ancient imperial Rome to peoples vanquished, put down and subjugated," they said.

Robert White, U.S. ambassador here during the Carter administration, earned the enmity of many righist Salvadorans for his public criticism of human-rights violations by parts of the country's security forces. Until Friday, Hinton generally had avoided clear-cut public complaints in line with the Reagan administration's emphasis on "quiet diplomacy" as the most effective way to deal with human-rights concerns.

But in a speech to the American Chamber of Commerce here, he said in unusually blunt language that the United States "could be forced to deny assistance to El Salvador" if the government fails to control "some elements of the security forces" and bring to justice those accused of involvement in the Jan. 3, 1981, murder of two American labor officials.

The American Chamber of Commerce and the Chamber of Commerce and Industry both include a number of wealthy families identified with the rightist politics advocated by middle-level officers suspected of complicity in the killings. Neither the target of Hinton's warning nor the source of today's response, therefore, was seen as accidental.

Queried about the attack on him today, Hinton declined to comment. His words Friday were viewed as a warning that the U.S. Congress could force the Reagan administration to end U.S. aid -- $230 million this year -- even though in the administration's eyes it is crucial to El Salvador's economy and the war against leftist guerrillas backed by Nicaragua and Cuba.

To continue the aid, the administration must certify to Congress every six months that El Salvador is making progress in human-rights protections. The next certification is due in January. Against this background, security officers believed to be acting without authorization from President Alvaro Magana or Defense Minister Jose Guillermo Garcia rounded up at least eight leftist politicians and labor activists two weeks ago, prompting increased concern about El Salvador's image in Congress and the U.S. public.