The South African Communist Party (SACP) has backed the Congress of South African Trade Unions' (Cosatu) decision to ban President Jacob Zuma from speaking at their events.
The party's spokesperson Alex Mashilo said although the federation has not officially informed them on their decision, the SACP respected them for their independence.
The African National Congress has remained mum on the issue, saying they were unable to comment until formal communication from Cosatu was received.
After Cosatu's special central executive committee meeting on Monday, the federation announced that they would support their workers in the call for Zuma to step down, and have therefore barred the president from addressing any Cosatu congregation.
Cosatu general secretary Bheki Ntshalintshali said on Tuesday executive committee delegates condemned the "divisive actions" by some leaders of the ANC who allegedly attempted to rent crowds in Bloemfontein to "hijack" and disrupt the federation's event on May 1.
They believed the booing and heckling of Zuma reflected the level of frustration felt by workers about the "absence of leadership" in the country and the "deteriorating" state of the country's political situation.
Zuma's address to the trade union federation's Workers' Day rally was cancelled after unionists wouldn't let him speak.
"The [special committee meeting] also took time to deal with the sentiments expressed by some of our members before May Day, who felt that allowing Zuma to address our event in Bloemfontein was inconsistent with our position calling for him to step down," Ntshalintshali said.
Cosatu reiterated they no longer trusted and supported Zuma's leadership.
"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 said.
"Cosatu remains very much committed to the [tripartite alliance] ... we also remain a reliable ally of the ANC."