"What's included in that is the capital expenditure required to start up the school, if we took that same approach to every new school and divided the cost of the building as well as their operating grant between the day one roll we would get figures like that as well."
However she told RNZ she could not give a more accurate per student average, as charter schools were funded in a different way to state schools.
"To say there is one average across 840,000 children and young people we should use is misleading."
The Herald reported some of the problems at Te Kura Hourua ki Whangaruru back in June.
But Ms Parata said it was still early days.
The school opened in February.
"Over half of their starting roll is at school, parents are supporting the school, they do have a curriculum...
This is having some effect but it is still in its early days."
Ms Parata said students from the school were on the margin, but the school's purpose was to re-engage them in education.
"These are kids who have had drug problems, these are kids who have been absent from schools, these are kids who are on the margin.
"But what's the alternative? To have these kids become another statistic in the justice system, or in the social welfare system?"
Labour's Education spokesman Chris Hipkins said Ms Parata's claims were an indictment on her own performance as minister and the policies of the current National government.
He said the suggestion that the alternative to at-risk children attending charter schools was jail were "disgraceful".
"It speaks volumes that the current Minister of Education has so little faith in our state schools she thinks the only way to cater for the most at-risk kids is to take them out of the school system and put them into an environment where they've been found to be constantly absent."
