The signing of the National Health Insurance bill — popular among voters—will come just before the May 29 national election that could test the African National Congress' 30-year rule.
The bill, which will be implemented in stages at a cost of billions of dollars, received Ramaphosa's approval after it was passed by lawmakers last year.
The law aims to provide healthcare to millions of poor citizens in a major overhaul of a two-tier system, which still reflects deep racial and social inequalities three decades after the end of white minority rule.
The legislation has been strongly opposed by business groups which say it will lead to disinvestment in the healthcare sector and damage South Africa's already fragile economy.
Political commentators say that concrete changes are unlikely to come soon even once the bill is signed.
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