Sirhan B. Sirhan, who is serving a life sentence for the 1968 assassination of Robert F. Kennedy, claimed in a television interview last night that he is being held as a political prisoner and that possible parole is being delayed on political grounds.

Sirhan asserted on "ABC News Nightline" that a hearing on his parole has been delayed until March, 1983, because of opposition by Los Angeles District Attorney John Van De Kamp.

Sirhan noted in the interview that Van De Kamp is seeking that state attorney general's office. "I would be a very easy scapegoat for him," Sirhan said.

Sirhan said Van De Kamp has made "totally untrue, unfounded" accusations that Sirhan had told a fellow inmate in January, 1980, that if. Sen. Edward M. Kennedy (D-Mass.) became president, Sirhan would "take care of him myself" if he were paroled in 1984. Sirhan also planned to involved himself in criminal activity after his release, Van De Kamp said.

Asked by interviewer Ted Koppel about the alleged threat to Kennedy, Sirhan replied: "May lightning strike me dead, sir, if I ever made that statement."

Van De Kamp said yesterday in a telephone interview that he opposes possible parole for Sirhan on Sept. 1, 1984 and denied any personal political motive behind his request that no parole be granted. Van De Kamp said he believes that Sirhan should not be released at that time. The nature of his crime should be taken into account, he said.

Sirhan fired eight shots, killing Robert Kennedy and wounding five others in the Ambassador Hotel in Los Angeles on the night of the California primary election in 1968.

The ABC interview was taped in California's Soledad State Prison earlier this week, but Sirhan would not allow television cameras to record the event.

In the interview, Sirhan claimed that he is "a changed man" and that he wrote last week to Sen. Kennedy to express remorse over the assassination of his brother. "That has been a sticking point in my throat even, that 12 [sic] children have to live fatherless," Sirhan said. (At the time he was killed, Robert Kennedy had 10 children. Another was born after his death.)

Sirhan read a letter from a Soledad chaplain that said: "Everything I know about him from regular and daily contact shows not the slightest interest in attacks on the Kennedy family or anyone else, and he seems deeply affected by the whole tragedy."

Sirham, a Christian Palestinian, told Koppel his mind was "dissociated" at the time of the shooting because he had been drinking liquor. Nevertheless, he insisted to Koppel that he shot Kennedy for political reasons and that psychiatrists have established the the Arab-Israeli conflict was "a very substantial force" in his mind.

Now, Sirhan said, all he wants to do is to "go back into the Arab world and just melt away into anonymity of its masses . . . and live out my life as peaceably as I can."

Sirhan said that he has requested letters from Arab envoys to the United Nations saying he would be welcome in their countries and that his first favorable reply was from Libya. "I have some reservations about going to Libya," he said.

Sirhan said he should not be treated differently from others who were sentenced to death when he was and subsequently released. He spent slightly less than three years on Death Row until the California Supreme Court voided the penalty.