President Cyril Ramaphosa on Wednesday appointed a judicial inquiry into the R2-trillion State pension fund, a government gazette said, following corruption allegations.

The PIC is Africa's biggest pension fund and the biggest investor in South Africa's economy holding a large volume of bonds issued by government and State-owned firms.

The gazette notice said it will investigate "persistent and continued negative reports about alleged improprieties regarding investments" by the Public Investment Corporation (PIC), which manages assets on behalf of the government employees.

Ramaphosa said the inquiry should issue a final report by latest April next year.

In May, opposition parties called for an investigation into the pension fund's chief executive Dan Matjila, accusing him of misuse of funds and careless investment decisions.

Matjila has denied the allegations and was also backed by the Treasury, which oversees the PIC.

The PIC's spokesman could not immediately comment and referred any questions to the Treasury.

In 2017, Matjila was cleared of any wrongdoing by an internal audit committee that looked into the allegations.

But the collapse of VBS Mutual Bank early this year, where the fund has a 25% stake, and the resignations of two PIC employees linked to the fraud have raised new questions.

The PIC also has stakes in blue-chip companies across various sectors such as miner Anglo American Platinum, lender Barclays Africa and retailer Shoprite.