NEW DELHI, DEC. 27 -- An Indian businessman denied in a statement published today that he had tried to pay a Virginia investigator to certify that Prime Minister Rajiv Gandhi was uninvolved in a scandal over alleged currency violations by Indian firms.

The investigator, Michael J. Hershman, has charged in court papers and in interviews that a Chicago attorney representing Indian businessmen living in America offered him $500,000 to write a letter exonerating Gandhi and his family members from any wrongdoing. Hershman is president of the Fairfax Group, based in Annandale.

The debate here over the activities of the Fairfax Group has given new life to a political controversy over corruption that at one point seemed to threaten Gandhi's political tenure. Last spring, Indian opposition figures accused Gandhi of aiding a coverup of alleged illegal currency operations by reassigning government officials who were investigating the matter and who had hired Hershman's company to assist the probe.

Gandhi's aides denied the coverup charges and a government spokesman declined comment on Hershman's charge of the bribe offer.

Hershman has said New Delhi businessman Ali Siddiqui and an Indian executive living in Chicago had joined with the attorney, Philip S. Wolin, in a meeting last year in which they had offered payment for a letter clearing Gandhi. Hershman said Wolin later telephoned and mentioned the $500,000 figure, saying the offer was on behalf of the Indian businessmen.

In a signed statement published in the Times of India, Siddiqui responded by saying that he "at no stage offered {Hershman} any money" or even discussed the prime minister with him. Siddiqui runs a New Delhi computer training facility with Adil Shahryar, a boyhood friend of Gandhi.

Siddiqui's statement said Hershman told him repeatedly in front of witnesses that "Rajiv Gandhi was not involved in any scandals." It repeated a charge by Wolin that Hershman had asked $5 million for information he had on alleged illegal activities by Indian businessmen.

Wolin has said he offered to pay for a report on Hershman's investigation, which initially had been commissioned by the Indian Finance Ministry. Hershman said he tossed out the $5 million figure, wanting "to see how far they would go." Hershman so far has not said what, if anything, his investigations have revealed about the prime minister or those close to him.

In 1986, Gandhi's then-finance minister, V.P. Singh, hired Hershman's company to probe alleged irregularities by major Indian business houses. Singh was transferred to the Defense Ministry and then resigned that post amid controversy over his corruption investigations. A judicial panel later was named to probe the Fairfax role in the currency investigation and its report was highly critical.

In the statement, Siddiqui acknowledged meeting with Hershman twice, but he otherwise appeared to distance himself from other Indian businessmen mentioned by Hershman and from their attorneys.