Investment in private community schools, also known as meridian schools, was intended to extend quality education to lower-income families, the Public Investment Corporation (PIC) said on Wednesday.
"Quality will no longer be a preserve of the elite," spokeswoman Nomzamo Petje said in a statement.
"It will create an opportunity for more South Africans in lower income households, access to the same standard of quality education currently enjoyed by the high end income households."
The PIC was responding to criticism from the Congress of SA Trade Unions (Cosatu) about its investments in the meridian schools.
On Tuesday, Cosatu spokesman Patrick Craven criticised PIC and Old Mutual Group Holdings' partnership with JSE-listed private education company Curro Holdings, under which R400 million had been injected into private community schools.
He said the funds could help narrow the gap between the two spheres of the schooling system.
Petje said the PIC invested the funds on behalf of public institutions and one of the asset categories it invested in was social investment, which included education and skills development.
Investing in education was also based on the Government Employees Pension Fund's mandate, which endorsed public-private partnerships to build new educational facilities.
"The expectation is that the fund will grow to R6 billion over time as other like-minded investors invest in it," Petje said.
As it grew, the second phase of the schools programme would prioritise the eradication of "mud schools"
She said that the investments were complementary to the government's aim of increasing education delivery.
The PIC believed that the delivery of quality education could not be tackled using a "single track approach".
"The interventions of non public education are significant in complementing the long term objectives of government and they will provide important choices for ordinary, and most importantly less privileged South Africans," Petje said.