Amid mounting calls for answers about a fire that killed six South African National Defence Force (SANDF) soldiers at the SA Army's Combat Training Centre in Lohatla in the Northern Cape on Friday, the SANDF has said it will launch an investigation into the matter.

SANDF spokesperson Siphiwe Dlamini said an investigation was standard procedure after such an incident.

He, however, said the investigation would commence once the SANDF had "mourned" and buried the soldiers.

Staff Sergeant Abraham Desember Morajane, Staff Sergeant Sipho Berrington Cele, Corporal Sithembiso Wiseman Ndwalane, Corporal Noxolo Faith Ngubane, Lance Corporal Prince Michael Mthethwa and Lance Corporal Londiwe Purity Zulu died in the fire.

Three other soldiers suffered second-degree burns, while others sustained minor injuries.

Among those who have lobbied for an investigation are the SA National Defence Union and the DA.

On Sunday, President Cyril Ramaphosa, the commander-in-chief of South Africa's armed forces, expressed his "profound sadness" at the deaths.

According to the Presidency, the troops were part of a military exercise named Vuk'uhlome.

The blaze is said to have originated as a wildfire in Khathu in the Gamagara Local Municipality and spread to the base, propelled by strong winds. The army lost vehicles, camp equipment, shelter and the personal belongings of 1 300 personnel.

The president offered his deepest condolences to the dead soldiers' families, friends and colleagues.

The Presidency said, "The president wishes the injured SANDF members a speedy and comfortable recovery, and his thoughts are with survivors who witnessed this tragedy."

Gift of the Givers announced that its teams were preparing aid packages to assist soldiers who lost their belongings and supplies in the fire.

According to founder Imtiaz Sooliman, the intervention came after the SANDF urgently requested clothing, underwear, hygiene packs, toothpaste, toothbrushes, soap, face cloths, hand towels, sanitary pads, energy drinks and blankets.

However, the SANDF has since denied requesting humanitarian aid.

The force said: "Material support offered by well-wishers, including the Gift of the Givers, is sincerely and heartily appreciated" and reassured "all concerned South Africans" that it was working hard to support deployed troops despite "dire financial circumstances".

"We respectfully want to correct reports that the SANDF has asked for assistance in this regard. We have not approached or requested anyone, individuals or corporates, for material support."