He said at the launch of a Human Sciences Research Council report on children and HIV: "I think throughout the world it was a very good idea to taper down the advertisement of infant feeding formulas.
"I think they must be banned altogether - throughout the whole world," he said, adding that he might propose the idea during discussion of the millennium development goals at the World Health Assembly next week.
One of the goals relates to infant mortality.
"When this is brought (up), because I know it's on the agenda, one would bring (up) these issues of infant feeding, because it's one of the key issues.
"If there's a move to ban infant formulas, I'll be one of the people to support it," he said.
Motsoaledi said there was always argument over the best method of feeding a child.
"But we know that breastfeeding is by far the best - all around the world nothing can ever beat breastfeeding."
If there were exceptions, they should be dealt with.
He knew he would shock people with his proposed ban, but formulas are "no different from skin lightening creams", which are banned in South Africa.
He emphasised that he was talking about milk substitute formulas, not other baby foods.
Motsoaledi, who at one time worked as a doctor in rural areas, said he knew that in those areas, women sought the slightest excuse to not breastfeed.
The World Health Organisation recommends that in most cases babies should be breastfed exclusively for the first six months.
In the mid-1970s, advocacy groups launched a worldwide boycott of Swiss formula producer Nestlé, accusing it of using unethical methods of promoting infant formula over breastmilk to poor mothers in developing countries.
The advertising of infant formula has been banned in the UK in recognition of the importance of breastfeeding since 1995.