President Thabo Mbeki was to join his Mozambican counterpart Armando Guebuza and Samora Machel's widow, Graça, at the site of the crash at Mbuzini in northern South Africa where Machel and 34 others perished in October 1986.
While some speculate the pilot of the president's jet had mistaken a South African airstrip for Maputo airport, many Mozambicans believe the then government in Pretoria had jammed the plane's radar.
Machel had signed a non-aggression pact with the apartheid regime agreeing not to let his country be used by the African National Congress, while Pretoria pledged to withdraw support to rebels fighting Machel's government.
The pact was a major blow to the ANC which had used Mozambique as a staging post for attacks. But while the move left a bitter taste in the mouth for many, the movement also expressed some understanding for Machel's decision.
The then ANC information secretary, Thabo Mbeki, said then that frontline countries were "not strong enough to resist South African pressure".
In a sign the new rulers of South Africa will let bygones be bygones, Mbeki paid homage to Machel last Friday in his weekly ANC newsletter.
He called him "our own national hero" and hailed the "indelible impact" that the former Mozambican president made in the fight against the whites-only regime.
Tom Wheeler, an analyst at the South African Institute of International Affairs, said Machel had little option.
"Probably economics, in the end, were the reason. The Mozambicans needed support from the South African economy," he told reporters.
"The sympathy was there but the money was not there. Without giving up his principles of being anti-apartheid, he did what he could."
Machel was particularly outspoken in his criticism of Pretoria for violating the accord in the months after its signing, encouraging speculation he may have fallen victim to regime agents.
"Apartheid, like Nazism, is not limited to internal repression but also looks to export conflicts beyond its borders," he told the United Nations General Assembly a year before his death. South African interest and affection for Machel was further bolstered by the 1998 marriage between Nelson Mandela and Machel's widow.
The couple divide their time between the two countries.
Born in 1933 in the southern Mozambican province of Gaza, Machel was the son of peasant farmers and endured a poverty-stricken childhood.
It was in 1961, while training to be a nurse in Lourenço Marques (modern-day Maputo), that he had a decisive encounter with Eduardo Mondlane, the founder of the Mozambican Liberation Front, better known as Frelimo.
In 1964, after military training in Algeria, he returned to Mozambique to launch the armed struggle. A remarkable strategist, he became the head of the armed wing of Frelimo in 1966. His rise through the ranks of Frelimo was swift.
After the assassination of Mondlane in February 1969, Machel assumed the leadership of the liberation movement which he steered towards independence on June 25 1975.
After his death, Mozambican authorities banned all reference to Machel in order not to undermine his replacement Joaquim Chissano.
It was not until six years ago that his name could be referred to again by the state media.
Although Guebuza was to attend Thursday's ceremony in South Africa, the Mozambican government's main commemorations will not take place until the 25th anniversary of his death in 2011 when a series of public monuments will be inaugurated. - Sapa-AFP