According to Business Day, the axe fell on Wednesday night after "a heated meeting to seal his future".
Some reports say the meeting lasted 10-hours.
A statement on the matter will be issued on Thursday.
Vavi has tweeted: "I committed an error & have profusely apologised to everyone hurt by my indiscretion. That was a right thing to do.
"I am relieved so many have accepted that apology and recognize that some remain unforgiving. Know others celebrating and rubbing salt.
"Thank you for the support - will say more later."
More to follow...
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