The Rand Daily Mail, which has been challenging the official version of a newspaper-funding scandal, won a limited victory last night when a court dismissed a government request to prevent the morning daily from publishing any new disclosures about the scandal.

A provincial-level supreme court judge refused a plea by the Erasmus Commission, a three-man judicial team of inquiry appointed by the government, to issue an injunction against the Rand Daily Mail prohibiting it from printing any further remarks by former information secretary Eschel Rhoodie, now living in Europe.

The decision was an unexpected boost for South Africa's opposition press, which is walking on thin ice as the country's worst political scandal appears to be threatening the tenure of Prime Minister Pieter W. Botha's administration. There are growing suspicions that government claims of protecting national security are an attempt to cover up politically embarrassing information. The English-language opposition papers, in particular the Rand Daily Mail, are pushing for full disclosures.

The latest court decision dismissing the Erasmus Commission's plea, however, cannot be regarded as a permanent victory for press freedom. A similar request by the commission against the Mail's sister paper, the Cape Times, was heard in the Cape Province Supreme Court today. Both are opposition papers published by the South African Associated Newspaper Group. The decision in that case is expected Wednesday.

There are fears that the government may pass legislation further restricting the press because of the scandal, which became known largely because of press probes. Two years ago the government threatened such action and only backed down when the papers agreed to adopt self-disciplinaty measures.

The Mail's vigorous reporting of the scandal and its latest venture in publishing Rhoodie's story have practically made it enemy number one for the government.

Since last Friday, the Mail has been publishing allegations by Rhoodie that contradict the findings of the Erasmus Commission. The commission found Rhoodie, the former minister of found Rhoodie, the former minister of information, Cornelius Mulder, and the country's former intelligence chief, Hendrik Van den Bergh, solely responsibile for the irregular funding of a pro-government newspaper called The Citizen.

In exclusive interviews with the Mail, Rhoodie claims the commission report is a cover-up and that the entire Botha Cabinet knew as far back as November 1977, of The Citizen's source of funding. His allegations have led to a major crisis for the sixmonth-old administration of Botha.

The Mail's victory Monday night came less than 24 hours after it had been ordered by a separate court action to excise three paragraphs out of a front-page story quoting Rhoodie.