Zambian President Edgar Lungu has been admitted to the Milpark Hospital, in Johannesburg.

He is to undergo a possible surgery for a blocked windpipe.

Lungu entered the hospital unaided, accompanied by Zambian Deputy High Commissioner in South Africa, Joe Kaunda.

The 58-year-old leader collapsed on Sunday while attending the commemoration of the International Women's Day at the National Heroes Stadium in Lusaka.

He was admitted to a Zambian hospital the same day and discharged on Monday.

His medical team reportedly recommended that he undergo high-tech surgery, not available in Zambia.

Before making his way to South Africa, Lungu told reporters in Lusaka that he was heading to South Africa for further medical treatment.

The Zambian Presidential Office said earlier Lungu felt fatigue and had traces of malaria.

"I am feeling much better and I have been told I have high levels of fatigue and should take some rest. There is nothing to worry about," Lungu said at the time.

Lungu won the presidential election in January 2015 after the late President Michael Sata's death left the post vacant.