The bank wants to support the country's reforms to split struggling power firm Eskom and to transition to a low carbon economy, it said in a statement.
Marie Francoise Marie-Nelly, the World Bank's director for South Africa, had told Reuters last month that the loan was under discussion and could come soon.
In Wednesday's statement, Marie-Nelly said reforms the government had launched would "benefit the people of South Africa - particularly the most vulnerable households - the economy, the environment, and advance the energy transition."
Eskom's coal-fired power stations routinely break down, leading to outages of up to 10 hours a day.
Several plants breached government emissions regulations earlier this year, according to a Reuters analysis published in September.
The World Bank said its Development Policy Loan would contribute to a gradual reduction in water and air pollution by reducing the reliance on coal for power generation.
South Africa's government pledged to split Eskom into three subsidiaries — transmission, generation and distribution — in 2019. In February, it agreed to take on 254 billion rand ($13.3 billion) of Eskom's debt, more than half its total debt, which was at risk of default.
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