South African investigators are investigating R10.5-billion of the government's coronavirus spending for corruption, more than double the amount they were investigating two months ago, they told parliament on Tuesday.

President Cyril Ramaphosa has promised that corruption during the Covid-19 pandemic will be dealt with harshly, after a spate of scandals sparked public outrage.

The Special Investigating Unit (SIU) said in a presentation to parliament that it had uncovered instances where personal protective equipment was overpriced, procurement rules flouted and services not delivered despite money being paid.

Most of the R10.5-billion under investigation was spent by provincial governments.

The SIU said in August it was investigating tenders worth R5-billion.

South Africa has recorded more than 700 000 coronavirus infections, the most on the African continent, with millions of its citizens losing their jobs or being pushed deeper into poverty this year.

Ramaphosa has likened those responsible for corruption during the pandemic to a pack of hyenas circling wounded prey.