South Africa dropped its case today against a leading Roman Catholic prelate, Archbishop Denis Hurley of Natal, who had been charged with falsely accusing a special police unit of committing atrocities in Namibia.

Hurley, 69, who is the leading Catholic figure in South Africa, was charged under a security law after saying at a press conference in 1983 that he had been given evidence of atrocities committed against civilians in the war zone of northern Namibia by a special police counterinsurgency unit.

The law makes it a crime, punishable by six months' imprisonment, to publish "false matter" about the police. The onus is on the accused to prove that what was published is true or that he took "reasonable steps" to check its accuracy.

Church observers from many countries, including the United States, packed the Pretoria courthouse today to hear prosecutor Frans Rudts announce that the charge against Hurley was being withdrawn because a tape recording had been found that he said differed from press reports on which the charge originally had been based.

Cheers greeted the announcement, and Hurley was mobbed by well-wishers afterwards, but there was skepticism about the reasons stated by the prosecutor for dropping the case. Some observers saw it not only as a vindication of the archbishop and the Southern African Catholic Bishops' Conference, of which he is president, but also as an indication that the state feared that more allegations of misdeeds would emerge if the case went ahead.

Hurley had warned that "a lot of dirt" would come out at the trial, and after his acquittal today he said at a brief press conference that he had mixed feelings. While he was pleased that the ordeal was over, he said he was disappointed that "what the trial could have brought out was not brought out."

The archbishop first made public accusations of misdeeds committed by South African security forces in May 1982, when he presented a report by church investigators.

The report alleged that the church investigators had been given evidence -- which they admitted they were unable to verify -- of widespread crimes committed by security forces in their war against African nationalist insurgents of the South-West Africa People's Organization.

The report claimed that the worst accounts implicated a special police unit code named Koevoet, an Afrikaans word meaning "crowbar." In February 1983 Hurley said at a press conference that he had been given further information and gave details of two cases that he said involved Koevoet.

In one, he said, two teachers died while being detained and interrogated by the police unit. In the other, a family of five had been mowed down by gunfire. It was the archbishop's statement about these two cases that led to the charges.