The trial of terror-accused siblings Ebrahim and Fatima Patel is expected to start in the Kagiso Regional Court on Wednesday.
A stun grenade and 21 rounds of ammunition were allegedly found in their house in Azaadville, on the West Rand, during a raid on July 9, 2016.
They were charged with violating the Explosives Act and Firearms Control Act.
They were released on R5 000 bail each after their lawyer, Yousha Tayob' brought an urgent application before the High Court in Johannesburg for their release.
They were allegedly linked to the self-styled Islamic State (ISIS) terror group and allegedly planned to set off explosives at a US embassy and Jewish institutions in South Africa.
Twins Brandon-Lee and Tony-Lee Thulsie, 23, were arrested during another raid on the same day.