The death toll in South Africa's unrest rose to 117 on Thursday as the country called up its army reserves in a bid to quell looting that has stoked fears of shortages and dealt a crippling economic blow.

The acting minister in the presidency, Khumbudzo Ntshavheni, told a news conference that Johannesburg, South Africa's economic capital, was now "relatively calm" while the southeastern province of KwaZulu-Natal (KZN) the epicentre of the violence "remains volatile."

The defence, security and police ministers and top army generals were dispatched to KZN to assess the situation and oversee the expanded deployment of security forces.

On Wednesday, the government said it would call out around 25,000 troops to tackle the emergency 10 times the number that it initially deployed.

"All reserve members are to report for duty at first light tomorrow morning 15 July 2021 at their respective units," army chief Lieutenant-General Lawrence Mbatha said in orders issued overnight as the unrest entered its sixth day.

Minister Ntshavheni said "by this morning, 10,000 boots were already on the ground".

Stores and warehouses in Johannesburg and KZN have been ransacked, devastating supply chains on which food, fuel and medicines depend in Africa's most industrialised economy.

South Africa's consumer goods regulatory body estimates that more than 800 shops have been plundered. At least 2,203 people have been arrested during the unrest.

Looting continued on Thursday in KZN, but the situation was quieter in Johannesburg, where volunteers in the city's townships took part in cleanup operations.

Residents lined up for their turn to buy food and other essentials at a mall in Alexandra township in northern Johannesburg that had been spared looting, as 20 soldiers patrolled the floors.

Volunteers took part in a cleanup operation at the Jabulani shopping centre in Soweto.

Community leader Musa Mbele-Radebe, 30, told AFP: "The use of the army is quite good, because our people are quite scared of the army compared to the police."