An Atlanta attorney representing a New York labor leader who was under investigation tried to approach President Carter - as well as Attorney General Griffin B. Bell - with claims that his client was being harassed by prosecutors.

Irwin W. Stolz Jr.'s June 9 letter to the White House, which Carter never saw, came nearly five months after the attorney and a colleague had tried unsuccessfully to approach Bell, another old friend, on behalf of Joseph P. Tonelli, president of the United Paperworkers International Union.

Tonelli and another union official were indicted Wednesday by a federal grand jury in Brooklyn on charges of embezzling $360,000 in union funds.

The indictment said that Tonelli converted $50,000 of those funds to his own use by hiring Stolz and W. Homer Drake Jr. to intercede on his behalf at the Justice Department. The grand jury rejected an argument by Tonelli - and the lawyers - that the $50,000 fee was a retainer for representing the union in civil rights cases in the Southeast.

Sources familiar with the investigation said the Brooklyn prosecutors are continuing the investigation to determine whether Stolz and Drake obstructed justice in their attempts to reach Bell and Carter.

In the letter to Carter, Stolz suggested that Tonelli would make a good liaison between the White House and organized labor according to White House spokeswoman Claudia Townsend.

Carter has not been looking for such a liaison, she said.

Stolz told the Associated Press that he wrote Carter saying he didn't think there was any substance to the investigation. He also alleged that his client was being harassed and intimidated, he said.

Though he mentioned the investigation, he did not intend to have Carter intercede, Stolz told the AP.

Carter was never made aware of the letter, and an aide responded with a two-line message thanking him for his regard for Tonelli.

Drake said in a phone interview yesterday that he and Stolz had been told by union officials that the federal investigation was over failure to keep vouchers for minor transactions. They based their representations of Tonelli's innocence on that information, he said.

Their firm, Swift, Currie, McGhee and Hiers, planned to bill the union for work they did for Tonelli personally, but decided against it, Drake said, when federal prosecutors in Brooklyn questioned its propriety.

Drake said that he didn't approach any other federal agency on Tonelli's behalf and didn't think Stolz did either.

Officials at the Labor Department, whose investigators assisted the Brooklyn organized crime strike force in the Tonelli investigation, said yesterday that they had no record of having been contacted by the Atlanta firm.

Francis X. Burkhart, assistant secretary in charge of such investigations, said in a telephone interview that he had never had any cotact at all with the two men.