PSA President Lufuno Mulaudzi said the association is in the process of resolving a matter before the labour court and it is unable to participate in a strike that is not protected.
"We are currently having a matter before the Labour Court about Resolution 1 of 2018."
"The events tomorrow are motivated by Section 77 certificate that was awarded to those who are participating tomorrow. It emanates from the joint action after parties realised there are issues in public transport, issues of job losses, corruption, OHS (occupational health and safety) and decent work. We are not part of that, tomorrow."
Cosatu has encouraged members that will be taking part in the strike to strike by staying at home or attending socially distanced pickets in their communities.
"The workers need to unite in defending jobs, fighting corruption as well as shortcomings of the law enforcement agencies in fighting corruption and gender-based violence," said Cosatu general secretary, Bheki Ntshalintshali.
"We need to fearlessly express our determination to protect the integrity of collective bargaining and to resist all attempts by employers to undermine it"
Mike Shingange, Cosatu's first deputy president said some workers have had to do tasks that are not part of their job description.
"You have nurses that are doubling up as cleaners. We're saying never again shall that happen when there is no incentive that recognises the fact that these workers are doubling up"
Cosatu and other unions hope that the government will take accountability and come up with solutions while protecting the jobs of its employees.