The ministry has suspended the Pacific Christian School's registration from the start of next term, the first time it has ever done so to a private school.
The school came under scrutiny last year, when an 11 year old stabbed another child with a pair of scissors.
Su'a has been dealing with the school, and says the move has come as a shock.
He says the sad outcome is the loss of the school's special character, as it is the only one which provides Tongan bilingual teaching.
"Because parents in my community are fighting to maintain language and culture. And I don't know whether any other school can provide
that special character that this school has provided, irrespective of the other issues that the school has to deal with."
Su'a William Sio says there is a clash of beliefs between the requirements of the law and the ministry, and the views of the school's leadership, over things including physical discipline.