Twenty-eight female guards were unfairly dismissed by a security company because the client‚ Metrora.
The South African Democratic Teachers Union in KwaZulu-Natal vowed to defy a court interdict that the education department won last week against its illegal strike.
But the department advised strikers to report for work this morning or face disciplinary action, including dismissal.
Sadtu said none of its office workers at the department in Durban, Pietermaritzburg and Empangeni will be at work today.
The department sought the urgent court order last week after thousands of its workers went on strike. The interdict ruled the strike illegal and allowed the department to take disciplinary action, including dismissals, against workers.
The order also restrains striking workers from impending access to the department's premises.
But Sadtu remains defiant.
"I will be in Durban this morning to make sure that if they arrest one of us they arrest us all," said Sadtu's provincial leader Sipho Nkosi.
He said about 7000 workers had been striking since last week over grievances ranging from racism by senior managers in the Pietermaritzburg office to unpaid service bonuses.
"This is not an illegal strike as the department likes to make out. We served notification to strike as set down by the Labour Relations Act on February 27," Nkosi said.
Education superintendent-general Cassius Lubisi said the department would act within the law to try to resolve the dispute .
"We want to ensure that service delivery is not compromised and will follow the legal route to the core in dealing with such matters. Should the employees fail to abide by the court order, the department will not hesitate to apply the necessary and relevant disciplinary action within the ambit of the law," said Lubisi.