Former president Jacob Zuma's attempt to privately prosecute News24 legal journalist Karyn Maughan and senior prosecutor Billy Downer has failed.

"The respondent (Zuma) is interdicted and restrained from re-instituting, proceeding with, or from taking any further steps pursuant to, the private prosecution," said Judge Paul Wallis in the KwaZulu-Natal Division of the High Court in Pietermaritzburg on Wednesday.

Zuma's bid failed after he accused Downer of leaking confidential medical information to Maughan in breach of the National Prosecuting Authority (NPA) Act.

Both brought applications to have the summons they were served reviewed and set aside.

In asking the court to set the matter aside, Maughan stated that Zuma did not obtain a nolle prosequi certificate against her.

The certificate is key to Zuma being procedurally allowed to privately prosecute.

In March, the hearing ended abruptly as Zuma's advocate, Dali Mpofu, made long-winded submissions and went at least an hour over his allocated time toward the end of the day.

Maughan's counsel, advocate Steven Budlender, argued in court that Zuma brought the charges against Maughan because of the former president's "extraordinary animosity toward her".