District of Columbia Mayor Marion Barry gave a convention of New Left activitists a "back to the basics" lecture here today, telling them their anticorporation rhetoric is almost incomprehensible to the poor and minority constituencies they are trying to organize.

Barry told the fifth annual Conference on Alternative State and Local Policies, meeting on the Bryn Mawr College campus, that "progressives" must return to emphasizing the 1960s goals of guaranteed adequate income, housing and health care.

Barry spoke at the closing session of the three-day meeting of local officials and union, community and public-advocacy organizers, many of whom, like Barry, are veterans of the civil rights and anti-Vietnam war movements.;

His message contradicted much of the rhetoric of the previous speakers, who argued that mobilizing against what they called the "corporate agenda" for America was the best basis for "progressive" politics in the 1980s.

"I understand why a welfare mother can't get turned on by a discussion of "the corporate agenda,"" Barry said. "She can't understand what you're talking about."

Earlier, in a news conference, Barry said the attack on corporate power was "good rhetoric for middle-class white progressives, but not for poor blacks or Chicanos." He said the relative scarcity of minority group members among the conference registrants was evidence of that problem.

Barry was one of the founders of the conference and has attended four of its five annual meetings. But his stand today put him at odds with many of its other leaders, including antiwar veteran Tom Hayden.Those leaders emphasized economic issues relating to what they see as corporate dominance of the American economy.

Barry also brushed over the energy issue, which has been a major focus of the meeting. Earlier today, United Auto Workers President Douglas Fraser drew applause when he announced that members of his union across the country will stop work briefly Aug. 26 to send letters to Washington, protesting rising oil prices and calling for stronger government action to control energy costs. "They will put down their tools and take up their pens," Fraser said, adding that the work stoppages are planned for only a few minutes on each shift.

Although his arguments appeared to be a minority position, Barry received a friendly response from those remaining among the original 1,000 registrants at the meeting.

And he proved he was willing, on some issues at least, to indulge in a little anticorporation rhetoric of his own.

Barry closed his speech by calling on the organization to make a "strong commitment to the liberation of South Africe."

"The same corporate giants who are oppressing us here," he said, "are oppressing our brothers in Africa."

He said "progressives" should resist any effort to recognize the new government of Aimbabwe-Rhodesia and should "tell the investment community in America, "don't invest one more penny in South Africa." "

"The corporate community," he said, "has a way of saying it should not get involved in politics. We know that's bull.... If they can get involved in politics for the sake of profit, they can get involved for human dignity."