She said the trust board, which leased the building from the Sisters of Our Lady of the Mission, had already run the hostel at a loss for several years and couldn't afford the $3.5 million to fix it.
"We spent about three years researching what we could do and if we could achieve it and came to the decision that we wouldn't be able to finance that," Mrs Jaques said.
The hostel has space for 105 boarders, including four self-contained flats for up to five students which were reserved for Year 13 students.
But Mrs Jaques said Euphrasie House had not been full for several years and last November's announcement had resulted in a further drop in first-year boarders.
The Mission Trust was trying to come up with homestay options for the remaining students but hostel manager Kris Burbery said Euphrasie House had become a way of life for the boarders and they were devastated at the closure.
"It's a big family. It's a family being broken up."
Mrs Burbery said boarders came from as far away as Korea, Australia, Kaitaia, Christchurch, Gisborne and Nelson.
Year 11 boarder Rebecca Burch, of Pukekohe, wrote that the announcement to bring forward the closure was a "huge shock".
"I still cannot believe that the place I have lived in for the past three years is closing. Everyone has been asking me what I will do next year and the truth is I don't know."
Mrs Burbery has been looking at options, including finding another building suitable for a hostel, but said it would ultimately be up to parents.
A group of affected parents have banded together to try to come up with a solution for their daughters.
A spokeswoman for the group, who did not want to be named, said the families were devastated by the new closure date. "Most of us are in the position that we need a boarding school and every other boarding school is booked up for next year."
The mother said the girls were established at Sacred Heart and parents did not want to uproot them.
"What we're feeling very devastated about is the fact that it was going to be closing at the end of 2012 and that was seen as a very short timeframe for us to be achieving anything. And now we've got three months."
A meeting would be held on Friday next week to discuss the situation.
David Kraakman, chairman of the separate Sacred Heart Girls' College board of trustees, said someone within the Catholic diocese was interested in buying the building potentially to use as office space.