Those gathered have started singing "we have arrived" while carrying placards written "create decent jobs" and "restructure the economy and create jobs for all".
The federation is the brainchild of former Cosatu boss Zwelinizima Vavi and the National Union of Metalworkers of SA (Numsa) along with other disgruntled former Cosatu members.
Vavi and Numsa were expelled from Cosatu in 2015.
Saftu will consist of 24 unions including the Food and Allied Workers Union (Fawu), which left Cosatu last year.
The federation has been long in the making following last year's Workers' Summit.
Irvin Jim, Numsa general secretary, says the launch of the federation was a journey that it was forced to take, but was the beginning of hard work.
"This will be the beginning of hard work. We will be building a federation now that will be both a shield and forest for workers," said Jim.
Some of the prominent people present include Jay Naidoo who's expected to speak and Mbhazima Shilowa.
Over the next following days union delegates will discuss various policies and the organization's constitution, the final name for the federation and elect its leadership.
POLITICS AND DEVELOPMENT BUREAU