Two newspaper editors here, and possibly a third, will go on trial Nov. 23 under a new press law for allegedly exposing South African intelligence activities during the abortive coup in the Seychelles Islands a year ago.

The editors are Rex Gibson of Johannesburg's Rand Daily Mail and Tertius Myburgh of The Sunday Times. Clive Kinsley, publisher of both, and reporter Eugene Hugo also have been charged.

Police have raided the offices and seized documents of a third newspaper, the progovernment Afrikaans-language Sunday paper, Rapport, but no charges have been filed.

The editors have been charged under the Protection of Information Act, which makes it an offense to publish any information relating to a security matter that might prejudice the country's interests.

The editors are accused of violating the law by publishing stories by Hugo naming two South African intelligence agents reputedly sent to the Seychelles after the coup attempt to assess the damage to South Africa's intelligence network there.

Hugo says he was given the names by a highly placed Seychellois source after Martin Dolinchek, one of the 54 mercenaries who tried to stage the coup, confessed to being a South African agent.

The government's decision to try the case reopens the question of whether it had a hand in the coup attempt. Lawyers say that, by bringing the charges, the state is conceding that the published information was correct.