Twenty-eight female guards were unfairly dismissed by a security company because the client‚ Metrora.
The KwaZulu-Natal department of education is probing allegations of bullying and intimidation levelled at the principal of Mandlakayise Primary School.
School head Francis Mthembu was recently reinstated as principal after a disciplinary hearing in 2006.
She was found guilty of accepting bribes to give unemployed teachers jobs and suspended for three months.
Yesterday provincial department of education spokesman Mbali Thusi said the department had assigned three of its officials to probe the matter.
The investigation comes after the National Teachers Union (Natu) asked for urgent intervention in the matter and called for a reversal of Mthembu's reinstatement.
Thusi said learning at the school had not been disrupted.
"The few teachers that are not part of the conflict are working hard and have combined classes so that learning continues without disruptions," Thusi said.
"The department has informed the union to choose one official out of three to start the investigation as soon as possible.
At least 17 teachers at the school have applied for special leave until the investigations into allegations of bullying and intimidation by their principal are completed.
"Two teachers have already been placed at other schools, while two others have applied for mutual transfers," she said.
About 20 teachers at the school downed tools a month ago after Mthembu was reinstated.
Natu spokesman Allen Thompson said the union was working with the department to speed up the investigation to protect their members from intimidation.
Thompson said several teachers had been receiving death threats from strangers, warning them not to continue opposing Mthembu's reinstatement.
Teachers who testified at Mthembu's previous hearing said they were surprised that she had been reinstated, especially at the same school.