Melbourne Senior Secondary College was shut down by authorities in July, forcing 83 VCE students to find new schools just months before their end of year exams.

Teachers have raised concerns about misconduct at the CBD school, which predominantly catered to international students, who were charged $18,000 a year in tuition fees.

International students said they were also told to pay thousands of dollars in extra fees or they would not be able to sit their exams.

One former teacher at the school, Stephen Pogany said he discovered in February that his student attendance records had been tampered with.

"Names of students I had never seen or recorded in my rolls were added to my rolls and fraudulent attendances added as well," he said.

Mr Pogany said staff were instructed to always give students a "satisfactory" mark and he was suspicious that some marks had been changed.

He said he was surprised to see a student who had barely attended his physics class sit a VCE exam.

"That student had barely ever attended my classes, had not submitted a single piece of work for assessment and expected to sit for the paper," he said.

One student said he and seven other international students were hit with an unannounced fee in mid-2015, despite having paid all their tuition costs.

He claimed his parents were told he would not be able to sit his exams and could be expelled if he did not pay.

The Victorian Registration and Qualifications Authority (VRQA) ordered the college to close because it breached rules governing overseas students. The school is appealing the decision in the Victorian Civil and Administrative Tribunal.

The Victorian Curriculum and Assessment Authority and the VRQA said they were not aware of allegations of phantom students.

But they said a VRQA investigation, launched in November, found the school's records were poor and it was difficult to determine how many students attended the school this year.

"There was contradictory evidence regarding whether some students attended classes."

They said there were inconsistencies with "satisfactory" marks awarded to students.

The VCAA said it had investigated the students' school-assessed course work for the past three years and found no evidence to revoke or change their final marks for each subject.

One student who has still not been placed in another school said she would have to repeat year 11.

She said many of the students were struggling with the upheaval, and questioned the VRQA's decision to close the school in the middle of the year.

"It's been really hard for the other kids in year 12, they only had one term left.

"The department did this with no second thoughts about the repercussions for students and teachers," she said.

"There are many other ways they could have handled the situation, they didn't have to close the school in the middle of the year."

The school's owner, Jan Wang, has not responded to questions from The Age.