The Kennedy Center and the New York Shakespeare Festival, two of the country's largest and most prestigious theatrical organizations, are planning to launch a joint repertory company in the fall of 1980 with stars such as Dustin Hoffman, Meryl Streep, Robert De Niro, Jill Clayburgh and Lauren Bacall.

The proposed company would perform as many as six plays a year -- mainly classics -- in Washington and New York. In addition, the two organizations would co-produce one new play and one new musical each season. Altogether, their alliance would fill almost six months of bookings in the Kennedy Center's Eisenhower Theater and another six months at a comparable Broadway theater.

"It's very exploratory," said Kennedy Center Chairman Roger L. Stevens last night. "What we're talking about may not have a chance of working, but we think we're going about it in the right way." The Eisenhower Theater schedule for 1980-81 has been kept open with the repertory company plan in mind, Stevens added.

Box-office stars are a major requirement, according to Stevens and Joseph Papp, who runs the New York Shakespeare Festival and the Public Theatre. pSo far, said Papp, the response has been encouraging. "And I know why, too. Because they [the stars] need it. They need this to continue developing their craft. And they're attracted to my organization."

Papp said salaries would be "realistic," with a top scale of perhaps $750 a week, substantially less than that paid stars in Broadway hits.

The company could cost in the neighborhood of $6-7 million for the first year, with perhaps $4-4.5 million recouped at the box office. Each organization would commit about $1 million at the outset.

Conceived to permit its stars to make movies for at least half of each year, the plan calls for a company split into two units. One would open in New York and one in Washington, and they would switch cities after two months.

Each unit would perform three plays in repertory -- starting with two, alternating titles several times a week and adding a third later. At the end of this four-month cycle, the two new works -- separately produced and cast -- would follow for about five weeks each, again replacing each other in the two cities.

If Papp's reputation and past associations are the keys to recruiting stars, the Kennedy Center with its subscription audience is what makes the plan financially feasible. Stevens and Papp have long harbored dreams of founding a national repertory company, and they both agree that New York City alone will not work as a site for it.

"The whole notion of a national theater, it's never made any sense to me before," said Papp, whose four-year reign at New York's Lincoln Center was probably the closest thing to a national theater the country has seen.

Known for his free summer Shakespeare in Central Park and for the pheonomenally successful "A Chorus Line," Papp withdrew from Lincoln Center's Vivian Beaumont Theater in 1977, explaining that his involvement there had adversely affected the rest of his operations, particularly at the Public Theater in lower Manhattan. The Beaumont has been closed ever since, although there are plans to reopen it next year.

"The only thing that makes [a national theater company] possible now is that Roger Stevens exists and also the Kennedy Center," said Papp.

Theater subscription plans have enjoyed little success in New York, although Papp hopes to launch one for the new company. "The problem in New York," said Stevens, "has always been that if the critics don't like something, then nobody goes to it."

Papp has described Washington audiences as "unsophisticated" but "very responsive . . . There's very little to do in Washington. A lot of people who would not go to the theater in other places do go to the theater." As a result, he has made frequent visits here over the last year, and for a time was keen to help start a new downtown theater in partnership with the Pennsylvania Avenue Development Corp. But the PADC was "just so slow," he said. "I speculated for a year, and I'm not going to speculate any longer."

Last spring, Papp and Stevens agreed to co-produce a play, Tina Howe's "The Art of Dining," which is now at the Public Theater and will open at the Kennedy Center next month. If the repertory company follows the pattern established by "The Art of Dining," Papp and Stevens will consult on major artistic decisions, but Papp and his organization will assume the day-to-day responsibilities of production.

Papp sees the company giving theater at the Kennedy Center "artistic continuity" instead of the present "potshot" appearance. "We would become the artistic base for the Eisenhower Theater," he said. The only organization that now performs for an extended period at the Kennedy Center every year is the National Symphony.

Besides famous actors, the company would have "some of the finest American directors," said Papp. He mentioned Andre Serban, Wilford Leach, Jack Hofsiss, Robert Allan Ackerman and A. J. Antoon as possibilities. As for plays, he said the emphasis would be on acknowledged classics. "We would certainly do Chekhov and Ibsen," he said, "but we might also do something by Tennessee Williams."

Lauren Bacall is now reading Chekhov's "The Sea Gull" at his request, said Papp.

The company would include young and unknown actors too, and would have an "affirmative action program within a competitive framework," he said. "The people will have to be first-rate."

Papp acknowledged that the plan might seem like an invasion of Washington by New York, but local people "will rally around what I'm doing, and I can help them." The plan is seen as a long-term venture, he said, and "once I get in there," Washington theater will develop "automatically."