The Food and Allied Workers Union made the decision to leave the Congress of South African Trade Unions.
This follows NUMSA being expelled last year.
Fawu General Secretary, Katishi Masemola, joins The Midday Report's Stephen Grootes.
Masemola says at the Fawu National Congress, the issue of Cosatu expelling Numsa was on the agenda.
Chief among other factors we considered in taking such a decision, was the fact that Cosatu had expelled Numsa. That to us was a watershed moment and the congress decided that we can't remain in a Cosatu that has expelled it's biggest affiliate.— Katishi Masemola, Fawu General Secretary
He says some members felt they could reform Cosatu from within, but overwhelming majority of delegates disagreed.
The union feels the Numsa expulsion was badly handled by Cosatu. And while being part of the tripartite alliance afforded the union power, they say they are now committed to being independent and are also exploring affiliating to an existing or new trade union federation.
When pushed on this issue, Masemola conceded that there was a strong possibility of forming a federation with Numsa.
A federation with Numsa would be a credible federation.— Katishi Masemola, Fawu General Secretary
He added that other unions may find it difficult to remain within Cosatu.
Meanwhile at a press briefing at Cosatu House attended by EWN's Masa Kekana, Cosatu General Secretary Bheki Ntshalintshali said they have been very patient with Fawu and are now concerned with the plight of farm workers who need protection.
Cosatu says the union has been weakened by a narrow political agenda. They insist they have been approached by many unhappy Fawu members who were unhappy with the decision to leave. Ntshalintshali says Fawu owes the federation millions of rand in membership fees, unpaid since their last congress.
Listen to the interviews below: