The woman visited her son, 23, in custody after his arrest at the weekend in connection with an armed robbery, said Warrant Officer Kay Makhubele.

"He told the mother when she got home she must remove his firearm from a drawer and hide it in the ceiling," he said.

However, after her visit, the woman went straight to police officers and told them of his plan.

Makhubele said the police took the man out of cells and back to his house to show them the firearm in the drawer.

"The firearm was found," he said.

The man would now face an additional charge of the possession of an unlicensed firearm when he appeared in the Protea Magistrate's Court on Tuesday on an armed robbery charge.

He allegedly robbed a shop in Naledi, Soweto, of airtime, cash, cigarettes and other items last month.

Makhubele said the mother had taught her son that parents did not always support children who got involved in crime.

"We applaud the mother for what she has done."