Johannesburg - A decision by Labour Minister Mildred Oliphant not to challenge a high court ruling on textile manufacturers was "absurd", Nehawu said on Monday.
"The decision of the minister not to challenge this ruling is troubling and absurd," the National Education, Health and Allied Workers' Union said in a statement.
"It is tantamount to negligence because those workers are being left [to] their own devices. The department of labour has got a responsibility to protect all employees at all times."
A group of five Taiwanese-owned factories and the United Clothing and Textile Association had asked the Pietermaritzburg High Court to set aside the minimum wages set by the bargaining council.
Judge Piet Koen ruled that factories which were not members of the council could hold separate talks about pay levels with their workers.
He found that less than half of employees in the clothing industry were represented on the National Bargaining Council.
Oliphant's spokesperson Musa Zondi said on Friday that she would not challenge the ruling, which stopped her from extending a bargaining council agreement to textile manufacturers and employees not represented by the council.
However, a later clothing sector bargaining council agreement, which was extended by the minister in September to members who were not part of the council, was still in force.
"This agreement has not been set aside. It would in any event constitute an unfair labour practice if any employer were to unilaterally change an employee's conditions of employment," Zondi said.
This later agreement remained in force until August 2015.
Nehawu said all companies should be forced to comply with the minimum wages set out in the bargaining council agreements.
"It is unacceptable that there are companies who want to continue to pay poverty wages to the workers and they are allowed by the department to use the courts to circumvent acceptable norms and standards," it said.
"The department should ensure that sectoral minimum wage agreements are enforced to guarantee that those who are at the bottom end of the economic pyramid benefit and the promise of a better life for all is realised."
It said it was disconcerting to see an "onslaught" against the Labour Relations Act by the Free Market Foundation, who want to challenge the constitutionality of the extension of collective agreements.
Zondi said on Friday that Oliphant and the labour department still supported a collective bargaining system and intended opposing the foundation's application.