The astonishing mix-up happened after the babies were whisked away after being delivered.
The babies were then handed to the mothers - without the women knowing that the child they were nursing wasn't theirs.
It took 12 hours for the mistake to be uncovered, following DNA tests.
The mix-up happened at Katleho Hospital, in Virginia, South Africa.
Spokesman Jabu Mbalula said:"Necessary precautionary tests and preventive treatment has been administered to the babies."
He said the tests were done to ensure that the babies' well-being was not compromised and that the children would suffer no ill effects.
The hospital had also provided the families with counselling and support. Internal disciplinary measures had been taken against staff.
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