After two fruitless atempts to prevent disclosure of facts in a deepening political scandal, South African Prime Minister Pieter W. Botha bowed to pressures yesterday and ordered a full judicial investigation into alleged corruption in the government.

The findings of the three-man commission will be released at a special session of parliament Dec. 7, Botha announced. Botha's reversal is an indication of the mounting pressures in the National Party-dominated government to pinpoint responsibility for the alleged misuse of millions of taxpayers' dollars found by a judge investigating currency exchange control violations.

According to testimony released Thursday, secret funds from the Information Department were used to finance The Citizen, a pro-government newspaper designed to fight criticism of South Africa's system of racial separation or apartheid.

Former Prime Minister John Vorster has already accepted "full responsibility" for allocating the secret funds to the Information Department, which was headed by Connie Mulder. He has not clarified, however, whether he knew in advance about the specific uses of the money, specifically the Citizen plan.

Botha tried Thursday to discourage Judge Anton Mostert from releasing the testimmony and also told the press that publication of the material would be against the law. Mostert disagreed with Botha and the press published the reports.

Botha admitted that he was aware secret funds had been appropriated to the Information Department to combat the "total threat" against South Africa. But, he added, "At no stage did I know money was allocated to The Citizen in any form."

Botha said Mulder, whose Information Department was scrapped after the first disclosure of its use of the secret funds, has agreed to testify before the judicial commission.