Chief Justice Warren E. Burger yesterday intensified his pressure on the nation's law schools and the organized bar to upgrade what he considers the poor performance of most lawyers in the courts.

He told the final session of the American Bar Association's policy-making House of Delegates that well-qualified trial attorneys form only "a thin crust" atop the rest of the profession and he asserted "the recall rate would be very, very high" if law school graduates were forced to meet the same type of standards that new cars face.

Burger's speech, which was greeted with polite applause by the ABA delegates, repeated a theme he has been sounding before bar groups in recent years. But yesterday he avoided the numbers game that caused such a controversy when he told the ABA last February that as much as half of the nation's trial lawyers are incompetent, and instead concentrated on the cost to society.

The chief justice said unskilled lawyers in the courtroom increase the cost of trials by extending them needlessly and often thwart justice.

Burger's solution, which he said a growing segment of the legal profession is beginning to embrace, calls for added training for lawyers before they are allowed to represent clients in the courts.

"If we fail to do this," he told the ABA, "we will not serve the cause of justice and our profession will not earn the respect of the public we are sworn to serve."

He said well-heeled clients of major law firms are well cared for since their attorneys have undergone inhouse training.

"But that reaches only a tiny fraction of those who go into American courts," Burger continued. "Far too large to proportion of lawyers in courtrooms today are engaging in on-the-job training, often at the expense of their clients and often at the expense of justice itself."

Responding to Burger, the ABA yesterday named a task force headed by Roger Crampton, dean of Cornell Law School, to study how law schools can improve the ability of their graduates in courtroom work.

In other actions yesterday the ABA's House of Delegates:

Refused to pass a resolution allowing television cameras in the courtroom even though a majority of chief justices of state courts had approved it and many states already are experimenting with television trials.

Approved revised "free press-fair trial" guidelines that ban judicial gag orders aimed at preventing news organizations from publishing information on trials.

Approved the use of television ads by lawyers.

Voted to support public funding of abortions for women covered by Medicaid who cannot afford to pay their own doctors for abortions.

Supported the international convention on the elimination of all forms of racial discrimination, which President Carter sent to the Senate in February. U.N. Ambassador Andrew Young told the ABA yesterday that the response of the united States to international legal convenants such as that one "has been particularly unsatisfactory." Young said Congress has failed t ratify at least five key international human rights conventions including a covenant against genocide.