A provincial police chief accused South Africa's police minister and other top brass Sunday of obstructing investigations into politicians, prompting parties across the board to demand an inquiry.

The uproar that followed the claims against police minister Senzo Mchunu forced President Cyril Ramaphosa to address the issue from a BRICS summit in Brazil, and call for restraint.

South Africa's stability and economic growth are undermined by its high rates of crime and corruption, including by organised networks.

KwaZulu-Natal Provincial Commissioner Lieutenant General Nhlanhla Mkhwanazi alleged Mchunu received payments from a corruption suspect and played a role in dismantling a team investigating killings to shield politically connected people.

The commissioner, speaking at a media briefing where he was flanked by armed security forces, some with their faces masked, said he had opened a criminal investigation into the minister, also accusing other officials of obstructing police work against organised crime.

‘Disturbing allegations’'

Mchunu rejected the allegations as "insinuations made without evidence or due processes", but said they would be looked into.

"This is a matter of grave national security concern that is receiving the highest priority attention," Ramaphosa said in a statement, committing to further action on his return.

Mchunu's African National Congress (ANC) party said the claims must be handled with "urgency and seriousness".

The centre-right Democratic Alliance, which has stepped up calls for Ramaphosa to remove government ministers accused of corruption, demanded an urgent debate in parliament.

"These disturbing allegations of corruption, political interference, and malfeasance at the very top of South Africa's law enforcement and national security infrastructure must be investigated immediately," it said.