Gervan Lubbe said his Malaria Monitor wristwatch, due to be launched next month, could save lives and keep millions out of hospital by preventing the disease before patients even feel ill.
Lubbe said: "It picks up the parasite and destroys it so early that the possibility of dying is absolutely zero and you don't even feel the early cold symptoms."
Malaria, caused by a parasite carried by mosquitoes, kills more than one million people every year and makes 300 million seriously ill, according to the World Health Organisation (WHO).
Ninety per cent of deaths are in sub-Saharan Africa.
The sturdy digital timepiece pricks the wrist with a tiny needle four times a day and tests the blood for malaria parasites. Three tablets that kill all traces of the disease must then be taken within 48 hours.
If the parasite count tops 50, an alarm sounds and a coloured picture of a mosquito flashes on the watch face.
Lubbe was approached by a major mining company to develop the device after it found that high levels of malaria among workers in Africa was hurting productivity.
"If you wait until you get symptoms and a malaria diagnosis you can be in bed for six months and have to take huge quantities of quinine which can be dangerous," Lubbe said.
His company, Gervans Trading, has already received 1.5 million orders for the wristwatch from companies, governments and aid organisations working in Africa, he said.
The watch will cost about $280, which Lubbe says is cheaper than treating a patient with severe malaria.
"It picks up the parasite and destroys it so early that the possibility of dying is absolutely zero and you don't even feel the early cold symptoms"
Malaria Monitor inventor
It also means people working or travelling in malarial areas can avoid taking expensive anti-malaria tablets which can cause serious side effects.
Mining companies can monitor miners by making them walk through a scanner each day.
The watch's radio frequency will transmit information of those wearing it to a central computer so health departments can ensure people at risk take tablets.
Lubbe said several African governments and the WHO had expressed interest in distributing the watch in rural Africa where access to treatment is scarce.
Lubbe, 38, won a gold medal for the world's best medical invention at the International Inventions Show in Geneva in 1998 for a pain relief device.