Mkhize was addressing a rally at Osizweni outside Newcastle in northern KZN for the arrival of the centenary torch in the province on Sunday.
His comments came two days after Malema criticised ANC president Jacob Zuma of dictatorship during a lecture at Wits University on Friday.
Mkhize told supporters that while the party accepted diverse views, the use of foul language and an attack on the party was unacceptable and would not be tolerated.
He also warned about the party running out of patience over bad behaviour.
“We hope that people can behave themselves before it gets to a point where the ANC gets fed up with unruly behaviour,” said Mkhize.
“The ANC has enough might to expel anyone who displays unacceptable behaviour inside the party.”
He emphasised that the ruling party was bigger than any individual and had in the past 100 years survived challenges by individuals who failed to follow party discipline.
Party national chairwoman Baleka Mbete echoed Mkhize’s sentiments of a party that needs disciplined young people who will lead the party in the future.
While not mentioning Malema by name, she said the party wouldl eventually run out of patience with unruly individuals.
The arrival of the torch marked the beginning of a host of activities by the ruling party in KwaZulu-Natal and will see the torch circulating around the province.
Among the key activities in April would be a lecture on former party president Josiah Gumede to be delivered by president Zuma in Durban later this month.