The South African Parliament passed sweeping new legislation yesterday to regulate fund-raising that could also be used to stop overseas contributions for the legal defense of persons charged with political crimes, most of whom are poor blacks.

The measure comes at a time when South African courts almost daily hear cases involving charges of a political nature ranging from the distribution of banned political literature to plotting the overthrow of the government. Security police recently announced that some 60 political or "terrorist" trials will involve about 300 persons.

The new power to interfere with overseas funds also comes as relations are at a low ebb between Justice Minister Jimmy Kruger and a sector of the legal community concerned about what it sees as an alarming erosion of legal civil rights through government legislation.

The new laws requires all private organizations collecting from the public to register with a new government-appointed director of fun-raising and to stipulate exactly for what purpose the funds will be used.

This official will have wide discretionary powers to prohibit the collection of funds for any project he disapproves. He can also order the interrogation of an organization's members and the seizure of its files if he suspects a violation.

One clause provides that money obtained from outside the country "shall be deemed to have been collected from the public in the republic," effectively placing overseas contributions to South African organizations for aid or defense of dissidents within the fund-raising director's ambit.

[In Washington, Millard Arnold, director of the Southern Africa Project of the Lawyers Committe for Civil Rights under Law, said the action by the South African Parliament was "regrettable and an other obstacle in the way of justice." Arnold said his organization, which has provide money frequently to aid in the defense of South African political prisoners, intends to continue trying to provide funds for such trials and "will go through the proper channels to try to test the law."]

Pro-government newspapers were sharply critical late last year when it was revealed that the American lawyers' organization contributed substantial sums for legal fees for the inquest into the controversial death in prison of black consciousness leader Steve Biko.

Tom Langley, chairman of the ruling National Party's Parliamentary Justice Committee, said, "When money comes from overseas for the support of so-called politically accused [persons], I consider that a flagrant interference in our internal affairs."

Under South Africa's legal system all defendants are given counsel if they cannot afford to hire an attorney. But in trials where the defense of an accused often depends solely on skilled and exacting cross-examination of state witness, expert legal aid is required, which most often comes at a price these defendants cannot afford.

Because local private sources in South Africa have not provided funds to hire quality legal defense "the burden . . . has fallen upon concerned church and civil rights groups from abroad," according to John Dugard, president of the South African Institue of Race Relations. "The legal profession should resist all efforts to cut off foreign aid funds for political trials, as without such funds the best defense will not be obtainable," Dugard said.