The High Court has ordered a magistrate to lift a reporting ban on a national security court case involving a disbanded group which used to organise the June Fourth candlelight vigil.

High Court judge Alex Lee's ruling on Tuesday would allow reporting on pre-trial proceedings in a case involving national security for the first time.

The successful appeal was brought by Chow Hang-tung, a former vice chairwoman of the now-defunct Hong Kong Alliance in Support of Patriotic Democratic Movements in China, who's charged with inciting subversion.

During committal proceedings, Principal Magistrate Peter Law had asked the media not to report on hearings against Chow.

Her lawyers had argued that reporting restrictions on committal proceedings must be lifted once the accused applies for the lifting of such a ban.

Lee said Law had "erred" in his decision. In his ruling, the High Court judge said the "magistrate's reasoning was totally in opposition to the principles of Open Justice that govern the exercise of judicial power in the context of restricting access to, or reporting of, court proceedings."

Lee added that his ruling doesn't affect the restrictions on bail hearings. (Additional reporting by Reuters)