A white supremacist who was plotting the genocide of black South Africans and a coup in the country has been jailed for life.

Harry Knoesen, 64, was the leader of a far-right terrorist group and had led plans to overthrow the government on 28 November 2019 using AK-47 rifles, hand grenades and rocket launchers.

Knoesen even wanted to use biological weapons to wipe out black people, the Mpumalanga High Court heard.

"He sought to justify his beliefs on religious grounds, claiming that God had ordained that he should reclaim South Africa for white people," said National Prosecuting Authority spokeswoman Monica Nyuswa.

In total, Knoesen has been handed two life sentences plus 21 years behind bars for terrorism-related offences.