Freshman Rep. Richard Tonry (D-La.) was elected to Congress because of fraudulent votes, a Louisiana state district judge ruled in Baton Rouge yesterday.

Tonry won an Oct. 2 primary runoff over former New Orleans Councilman James Moreau by 184 votes. But Judge Melvin Shortess said yesterday a minimum of 229 fraudulent votes had been cast for Tonry and 25 for Moreau, enough to change the outcome.

"But for the irregularities and fraud, Moreau would have been nominated in the second Democratic primary on Oct. 2, 1976," Shortess said in his 17-page ruling.

Despite the judge's decision, only Congress has the power to unseat one of its members after "he has been seated, and that action is extremely rare. The only member unseated in recent times was Rep. Adam Clayton Powell (D-N.Y.) on Jan. 10, 1967, for missing committee funds, Powell was only the sixth member in history to be unseated.

House Speaker Thomas P. (Tip) O'Neill, asked to comment on the Tony case, would only say, "We've got our committee looking into it and we're awaiting a report."

Rep. Mendel Davis (D.S.C.), chairman of thee-member ad hoc unit of the House Administration Committee looking solely into the Tonry case, could not be reached for comment yesterday. He has staunchly maintained in the past that Congress is the sole arbiter of Tonry's fate.

Tonry repeatedly has said he would not resign. "I think it was a meaningless decision just like it was a meaningless trial," he said yesterday. "Every attorney agrees . . . that the final decision lies in Congress."

He said he was submitting evidence of voter fraud by the other side to the House Administration Committee. "I am confident that the committee up here . . . after seeing both sides, will decide in my favor," Tonry said.

He said he doubted he would appeal the court ruling but would consult with his lawyers before making a decision.

Shortess' ruling yesterday annualled an earlier one in which he said there had been vote fraud but not enough to overturn Tonry's narrow history.

Gibson Tucker, Moreau's attorney, had pleaded with Shortees in closing arguments last week to overturn his original decision. "We suggest that the court was hopelessly duped from the outset," Tucker had said.

Twenty poll commissioners in the St. Bernard Parish district pleaded guilty in federal court to stealing votes for Tonry, and some of them swore that Tonry himself voted illegally in a precint where he was not registered.

There have also been reports of vote frauds on behalf of Moreau, and Tonry said he would present evidence of this to the House probers.

Tonry contends that the U.S. attorney who prosecuted the case was aligned with local political bosses who opposed him. "These charges were nothing more than an attempt to smear me. If they can't unseat me they are going to try to smear me so I can's be re-elected," Tonry said.

Tonry said it cost him $75,000 to dejury is probing charges of illegal campaign contributions to his election effort, and Tonry said if an indictment comes he may have to defend himself because he can no longer afford to pay private attorneys.