Some leaders of Cosatu felt that allowing Zuma to speak was "inconsistent with the call for him to step down", said Cosatu general-secretary Bheki Ntshalintshali.
"The one-day special central executive meeting agreed with the position of the workers that the decision to allow comrade Jacob Zuma was not consistent with our position that we no longer trusted and supported his leadership," said Ntshalintshali.
"The meeting ultimately resolved that going forward, in respect of the workers' mandate and in line with resolution of the CEC that he step down, President Zuma will no longer be welcome to address Cosatu activities ... "
"This shall be communicated to the ANC, including engaging on its implications for our alliance," Ntshalintshali told reporters in Johannesburg following a special executive committee meeting.
The stance by the trade union federation's national executive committee comes after Zuma was booed at Cosatu's Workers Day celebrations in Bloemfontein in May.
Zuma was unable to address the crowds and speeches were subsequently cancelled on the day.
It was the first time in the history of Cosatu that an ANC president was prevented from addressing a May Day rally.
Alliance partners Cosatu and the SA Communist Party (SACP) have publicly called on Zuma to resign, citing his leadership style and scandals such as Nkandla and rampant corruption, cronyism and factionalism burdening the governing party.
When asked whether Cosatu leaders and its members were in turn barred from events where Zuma would be taking part, Ntshalintshali said such events would be ANC events, not Zuma's.
"When the ANC invites us, it is not the President's invite to us. There will be other many activities where we will engage in policy matters ... and we will go and take part in such activities."
He added that Cosatu sent an invite to the ANC to send its delegates to the Workers Day, and that it did not ask for Zuma specifically to attend.
African News Agency