After the dismissal in October this year, Ms Ward took her claim to the Employment Relations Authority, which has released its decision that Ms Ward should reinstated in her role.
Ms Ward said in an affidavit to the authority that the comments were not meant to be included in the final testimonial but were for tutor group teachers to use "as they wished" in writing the students' testimonials.
The testimonials were sent unedited to three students so they knew their applications were complete, she said.
When principal Steve Robb was alerted to the comments, he tried to meet Ms Ward to discuss and find out more about the comments.
Ms Ward engaged a lawyer and provided evidence that she was medically unfit to participate in any meetings.
On October 10, Mr Robb sent Ms Ward a letter saying she had been dismissed for serious misconduct.
The letter said Ms Ward had undermined the school's trust in her, breached the school's professional conduct code and fallen short of professional standards published by the Ministry of Education.
Authority member Robin Arthur said in his decision that a full investigation by the authority would examine whether Ms Ward had been unjustifiably dismissed or whether the school was justified in dismissing her.
Until then, Ms Ward would be reinstated at the school. Whether she would be a contributing head of department or on 'garden leave' was up to the school, he said.
The school objected to Ms Ward being reinstated, and said two other teachers in the chemistry department would resign if Ms Ward returned to work at the school.
Mr Arthur said this was second-hand or hearsay evidence and couldn't be taken in to consideration.
The Board of Trustees submitted permanent reinstatement of Ms Ward would be futile given its loss of trust and confidence in her as a result of her "disparaging" testimonial comments and her conduct through the disciplinary process.
Mr Arthur ruled there was a case, albeit weak, that Ms Ward was unjustifiably dismissed, therefore she must be reinstated while the investigation was undertaken.
"She was entitled to have her own thoughts and criticisms about colleagues and students if she felt, for instance, that there were ongoing issues about how she was treated at school," Mr Arthur said.
"However, expression of such matters should responsibly have been made to the appropriate managers and colleagues in the appropriate forums."
Comment was being sought from St Peter's and Ms Ward.