You Do Need power plug adapter while traveling from Austria to South Africa.

Here is Why You Need An Adapter

The outlet and plug type used in South Africa are C, M and N and in Austria are C and F. This is how they look like.

Austria

In Austria, outlets of type C and F are in use.

Type C

Type F

South Africa

In South Africa, outlets of type C, M and N are in use.

Type C

Type M

Type N