A construction worker fell several metres at a site off the N3 in Drummond, KwaZulu-Natal, on Thursday after his step ladder gave way.
Netcare911 spokesman Shawn Herbst said the man fell about 9 metres.
He sustained serious injuries and was placed on advanced life support.
Herbst said the Netcare 5 specialised helicopter had to be activated to airlift the man to hospital.
The incident happened at around 4pm.