The incident involving the 26-year-old happened in the early hours of Saturday morning in the township of Kroonstad in the Free State province.
Ntuka, who had also been capped five times by South Africa, never featured at senior level for the Blues after his move to Stamford Bridge in 2003.
A representative from his agent Stella Africa confirmed the sad news this morning.
"I spoke to his wife for a couple of minutes and she confirmed that Ntuka has passed away after being stabbed in a township in Kroonstad," Michael Hughes told IOL.
"Unfortunately, trouble seemed to follow Jeffrey around. He tried hard to surround himself with the right people and club-mates. But he struggled to really shake the image and stories that dogged his career."
Ntuka spent six months at Chelsea playing for the reserve team in 2003 before being loaned out to Belgian club Westerlo for five years. He returned to his country to represent the Kaizer Chiefs in 2009.