Franklin Lamb, a self-described specialist in international law who charged in an article in Wednesday's Washington Post that Israel had "flagrantly violated" agreements with the United States by using cluster bombs against civilians in Lebanon, has been in repeated controversies involving charges of misrepresentation.

The Post, which was not aware of the controversies in Lamb's background at the time, reported that he was preparing a report based on a month-long fact-finding trip to Lebanon and that he hoped to persuade the president and Congress to declare Israel guilty of violating U.S. restrictions on use of cluster bombs and make permanent a temporary ban on their shipment to Israel.

Israel, while admitting it used cluster bombs in Lebanon, has insisted that they were "used only against military targets."

Lamb could not be reached for comment last night.

Lamb, 38, was at the center of a controversy this summer when United Press International carried a report that said:

"A U.S. congressional delegation investigating possible Israeli violations of arms sales agreements Saturday charged Israel used a U.S.-built vacuum bomb to flatten an eight-story building in West Beirut.

"The vacuum bomb is designed to suck air out of the target over which it is detonated and causes an implosion that destroys the target . . . . The building was demolished without any sign of fire or shrapnel, while surrounding buildings were unscathed.

" . . . The Soviet news agency Tass said in a dispatch from Beirut it was the first time 'in the history of military operations' that a vacuum bomb had been used operationally."

The New Republic, in an article published Sept. 6, reported that it had determined that "the official congressional delegation of which Lamb was a member turned out to be neither official, nor congressional, nor a delegation."

The magazine, which also quoted Pentagon officials as saying that the so-called vacuum bomb only "exists in the mind of Tass," observed that UPI had been "snookered by a pro."

Lamb, The New Republic reported, served from 1976 to 1979 as a member from Oregon on the Democratic National Committee. He was a contributor to The (Portland) Oregonian until the newspaper challenged the authorship of two articles on China appearing under his byline in June, 1978, the magazine said.

Later that year, The New Republic reported, the Justice Department accused Lamb of paying for a trip to Taiwan for 18 of his DNC colleagues with money obtained from a front group for Taiwan's nationalist government without registering as a foreign agent.

Lamb said the idea for the Taiwan trip originated in the committee's China Task Force. However, then-DNC chairman John White said the committee did not have a China Task Force. The New Republic also reported that Lamb's resume on file with the DNC contained "several inaccurate claims."

In March, 1980, Lamb identified himself as a member of Sen. Edward M. Kennedy's presidential campaign staff and issued a statement -- carried by The New York Times -- calling for most-favored-nation trade status for the Soviet Union and establishment of an independent Palestinian state. The next day, The New Republic said, Paul Kirk, Kennedy's political director, banished Lamb, who said he had been an unpaid volunteer.

A reporter for The Oregonian reported in May, 1980, that Lamb was listed "as a defendant in at least 11 cases filed in Multnomah County Oregon District and Circuit Courts." The New Republic said some of the suits requested recovery of bank overdrafts, payment for moving expenses and recovery of unpaid student loans.

On Dec. 30, 1981, customs officials apprehended Lamb in New York and sent him to jail for failing to show up in Portland for trial on three misdemeanor counts of charging telephone calls to other people's accounts, The New Republic said. He was found guilty on two counts on Jan. 15 of this year.

The magazine said a presentencing report on the telephone fraud recommended that Lamb receive six months in jail. But he skipped the sentencing hearing, and FBI officials are investigating additional charges of fraud, the magazine said.