The Congress of South African Trade Unions (Cosatu) will study two forensic reports on the union federation and if necessary point out illegal activities to law enforcement agencies.
"Where there are issues of fraud and corruption... they must be reported to the law enforcement agencies accordingly," Cosatu deputy general secretary Bheki Ntshalintshali told reporters in Johannesburg on Tuesday.
"We must interrogate the two reports and seek legal and expert advice where necessary."
Earlier, Ntshalintshali said a special central executive committee (CEC) meeting held on Monday and Tuesday had decided to dismiss general secretary Zwelinzima Vavi with immediate effect.
"The conduct of the general secretary constitutes gross misconduct," he said.
"Comrade Zwelinzima Vavi is dismissed as the general secretary of Cosatu with immediate effect."
Vavi was told of his dismissal and advised he could appeal it, in line with the federation's constitution.
All Cosatu staff were told to avoid contact with Vavi.
"All staff members, particularly provincial secretaries of the federation and of our unions, are instructed to desist from participating in comrade Zwelinzima Vavi-led activities," he said.
During a question and answer session, Cosatu president Sdumo Dlamini reiterated this.
"Leaders and workers... should not give platforms for him to speak to them on Cosatu matters.
"Neither should they go to platforms that are opened in his name."
Ntshalintshali said he did not know if Vavi had responded to his dismissal letter because they had been in the CEC meeting all day.