Police Minister Bheki Cele said the soldiers will work alongside the police in an operation to recover illegal firearms and drugs.
At least 13 people were killed in 24 hours last weekend in one of the violence-hit parts of the city.
Cape Town’s gang problem goes back many decades.
Local reports say the recent upsurge in violence is due to a turf war between rival gangs, fuelled by retaliation attacks.
There is a heavy police presence in Bonteheuwel, Delft, Hanover Park and Philippi East townships, reports say.
Mr Cele said the deployment was part of “extraordinary” measures that needed to be taken to ensure public safety.
“We’ll go door to door, we’ll collect every illegal firearm, we’ll collect all criminals that we want, we’ll collect all outstanding criminals that have been on bail and that is happening from two o’clock this [Friday] morning,” Mr Cele told the media.