Ntola was suspended last year after allowing Congress of SA Trade Unions general secretary Zwelinzima Vavi to address a union gathering in Port Elizabeth in the Eastern Cape, SABC news reported on Monday.
At the time, Vavi was still under suspension within Cosatu. His suspension was lifted earlier this year.
Ntola told the SABC that his expulsion was part of a political conspiracy to silence him.
“I knew from the very beginning even before those ‘wishy washy’ investigations started… I knew it was just to justify how they can take me out of the organisation,” says Ntola.
The provincial union said it would fight his expulsion by its national body, while the National Union of Metalworkers of SA (Numsa) also criticised the decision to expel him.
Ntola was a staunch supporter of Vavi, who is now back in his Cosatu position after winning a court case against his suspension for having an affair with a junior employee.
Sadtu has been divided on Vavi, with some factions calling for his removal while others are aligned to Ntola.