South Africa's President Cyril Ramaphosa has placed Police Minister Senzo Mchunu on an immediate "leave of absence" after allegations of links to organised crime were made against him.

In Sunday's live televised speech to the nation, Ramaphosa also announced a judicial commission would probe the claims, which he said undermined the constitution and threatened national security.

He added that law professor Firoz Cachalia had been appointed as interim police minister.

Mchunu denied any wrongdoing, saying in a statement that he "stood ready to respond to the accusations" against him.

In his speech, the president said that the allegations against Mchunu, which include interference in investigations into political killings and corruption within law enforcement agencies, "call for an urgent and comprehensive investigation".

He said the judicial commission, led by the country's deputy chief justice, would examine all the claims.

The commission will also investigate current and former police officials, as well as members of the national executive, Ramaphosa said.

Ramaphosa has been under growing public pressure to act swiftly over the high-profile case.

Mchunu, 67, is an influential figure in Ramaphosa's African National Congress (ANC) party.

Political analysts have suggested he could run for a leadership position at the ANC's next elective conference in 2027.

In a statement, Mchunu said: "I welcome and respect the president's decision and pledge my commitment to the process.

"Honour and integrity are the virtues I personally subscribe to and which we all need to make efforts to uphold."

The allegations were first made public by KwaZulu-Natal provincial police boss Nhlanhla Mkhwanazi last Sunday.

He claimed Mchunu was receiving financial support from an allegedly corrupt businessman to fund his "political endeavours".

Gen Mkhwanazi also detailed a sequence of events he claimed led to the "orchestrated" disbandment of a task force that was set up in 2018 to investigate the killing of politicians, mainly in KwaZulu-Natal.

He said the team's investigations had uncovered links to high-profile individuals - including politicians, police officials, and businesspeople tied to a drug cartel syndicate - and this is why the team was disbanded.

When he dissolved the unit earlier this year, Mchunu said it was not adding value in the province, despite many cases remaining unsolved.

According to Gen Mkhwanazi, a total of 121 case files were allegedly removed from the unit on the minister's instruction and without the authorisation of his boss, the national police commissioner Gen Fannie Masemola.

"These case dockets have, since March, been sitting at the head office ever since without any investigation work done on them. Five of these dockets already had instructions to [effect] arrests," Gen Mkhwanazi said.

He also alleged Mchunu had ties to a controversial businessman who was "financially supporting" the minister's political career.

Vusimuzi Matlala had a lucrative contract with the police before it was abruptly cancelled when he was arrested for attempted murder in May. Gen Mkhwanazi shared copies of text messages and a payment allegedly made by Mr Matlala to prove this.