A Melbourne high school teacher who tampered with students' grades should not have been reinstated, according to the state's education department.
Maths teacher Saji Paul was sacked over the tampering scandal in 2017 where he altered the grades of 16 students at his school.
He was later reinstated by the disciplinary appeals board despite the finding that Mr Paul had "sufficient motive" to alter the academic results and made "unauthorised" changes to grades.
A father of one student who had marks downgraded complained about Mr Paul's marking while another raised concerns about "inappropriate conduct".
That complaint was upheld and a warning was issued. Three days later changes to the marks were made in the online system.
Mr Paul did not teach the other students who had their grades downgraded, but they were taught by teachers who he clashed with over a maths program.
The education department secretary wanted the board to review the decision to reinstate Mr Paul but was knocked back in the Supreme Court. That ruling is being appealed.
The teacher denied the allegations and told the board the changes came from his account, but he was not behind the alterations.
"He has continued to deny the conduct and has not acknowledged the wrongfulness of it," education department barrister Claire Harris QC told the Court of Appeal on Tuesday.
Mr Paul's lawyer said the teacher had been demoted and it was a "serious and heavy" sanction. He was also reprimanded.
The board ruled the sacking had been "excessive" and it was the first time he engaged in misconduct.
The Court of Appeal judges reserved their decision.