A woman -- reportedly a local Boeremag leader -- was arrested on a Carolina farm for being in possession of unlicensed ammunition and explosives, Mpumalanga police said on Thursday.

Lt-Col Leonard Hlathi said she was arrested on Wednesday and briefly appeared in a Carolina court, but he could give no further details.

"On the issue that she is part of the Boeremag, I can't confirm that. I also can't disclose the locality where she is being kept."

Beeld newspaper reported that she was arrested during a police raid on her farm. Police suspected Cornelia de Wet, who was pregnant, made her farm available for the promotion of racist indoctrination, according to a police affidavit seen by Beeld.

The police said in a statement they had been investigating accusations of terrorism and treason for some time.

During the raid police confiscated ammunition for shotguns, and R1 and .22 rifles. After her appearance in court she was transferred to Middelburg prison. She would appear in court again on Wednesday, Beeld reported.