25 July 1971
Joe Kachingwe was appointed Malawi's first Ambassador to South Africa and assumes office in Pretoria on 29 July 1971. This diplomatic move by both countries followed a state visit by South African Prime Minister, B.J. Vorster in May 1970. Vorster and his party, the National Party (NP) were enthusiastically received in Malawi. Following this visit by Vorster, the status of the diplomatic missions between Malawi and South Africa improved to that of embassies. In June, the Organisation of African Unity (OAU) resolved that member-states should not engage in dialog with South Africa, but Malawi President Kamazu Banda ignored the resolution by visiting the country.
References

O’Malley, P. ‘1971’, from Nelson Mandela Centre of Memory, [online], available at www.nelsonmandela.org (Accessed: 21 June 2013)|

A Survey of Race Relations in South Africa 1971, in the South African Race Relations, p. 100|

Kalley, J.A. and Schoeman, E. (1999) ‘Southern African Political History: A Chronology of Key Political Events’