The Department of International Relations and Cooperation (Dirco ) says it will engage the diplomatic representatives of the five countries which have written a memorandum to President Cyril Ramaphosa warning him that failure to act against those implicated in corruption placed foreign investment at risk.

The embassies of the United States of America, the United Kingdom, the Netherlands, Germany and Switzerland dispatched a letter to Ramaphosa voicing their concern about corruption and other crimes, in what has been described as an unprecedented move.

Dirco has described the move as a departure from normal diplomatic protocol. Minister Lindiwe Sisulu has instructed the department to “demarche the concerned ambassadors with a view to discussing substantive matters contained in their correspondence, and to reiterate acceptable protocol in addressing such matters,” according to a statement issued on Sunday.

“This is a departure from established diplomatic practice,” it said.

Dirco further stated that in terms of acceptable diplomatic practice, protocol and convention, diplomatic missions are “expected to communicate to the receiving state by means of a note verbal (diplomatic note)” conveyed through the department.

The memorandum by the five nations came as evidence before the commission of inquiry which is probing allegations of state capture detailed allegations of corruption against some government officials.

Earlier, the commission headed by Constitutional Court Judge Raymond Zondo, heard how the wealthy Gupta businessmen used their political influence to obtain government contracts. The commission has also heard how a services company, Bosasa, paid bribes to senior government officials and African National Congress (ANC) members to win favour.

“No investor would venture to come to South Africa without proper and comprehensive guarantees for his investment,” read a passage quoted by Sunday Times.

Since his appointment in February 2017, Ramaphosa has embarked on a mission to boost foreign investment into the country, in a bid to stimulate the economy.

He has set a target of raising $100 billion over the next five years and appointed a special investment envoys tasked with selling the country abroad.