David Ofori Acheampong, General Secretary of GNAT, said there are rules and regulations governing the association, hence, members who break those rules must be sanctioned in accordance with the guidelines.
The Ghana Education Service (GES) on Friday, 23 November announced the sacking of Mr Seppey for sexual misconduct.
In January this year, a video of Mr Seppey having sex with his former pupil on a kitchen stool went viral on social media. The GES took over the investigation from the police after it was discovered the victim was not a minor and the affair was consensual.
Five other teachers were also sacked for sexual and moral misconduct.
Three of the teachers have been convicted by the court for stealing, thus, their dismissal. One teacher has also been convicted of defilement.
According to a statement from the GES, the teachers were made to go through due process before the punishment was handed down to them.
Reacting to the news on Ghana Yensom on Accra 100.5FM hosted by Kwabena Prah Jnr. (The Don) on Friday, Mr Ofori Acheampong said: “There is no perfection on this earth that is why people break the law. If you misconduct yourself, there are sanctions for it.
He added: “GNAT had a representation on the committee that sat on the matter and, so, we welcome the decision.”