The Presbyterian Church has described Turakina Māori Girls' College as a 'jewel' that should not be lost.
The Ministry of Education is considering closing the Marton kura after its roll fell to just 54 students this year.
The church said it was working on a plan to give to the Minister of Education by the ministry's deadline of next Friday, showing why the boarding school should stay open.
A government report blamed the college's financial problems and rundown buildings on the Trust Board - the school's proprietor - which is part of the Presbyterian Church.
The board's commissioner Kathie Irwin said the kura was a "jewel" that must be kept.
"That description gives you a very strong statement from the church itself about how they feel about Turakina. This is the only Māori boarding school that the Presbyterian Church has a connection with.
"For us as a people, we would say 'he taonga, he taonga te kura a Turakina' [it's a treasure, Turakina is a treasure] - that is where the church and the proprietors are working to make sure that jewel is still a jewel of the future."
Dr Irwin said there was a niche that Māori boarding schools occupy and the church wanted to ensure that specialist area was protected.
"When we think about the demographic for New Zealand moving forward, we know that it is a young, brown demographic, and 50 percent of that is women. So to only have three specialist schools [for them], that's not a lot of resource to be educating the future leadership of Māori women."
With such a limited resource to educate wahine rangatira (leaders), it was imperative Turakina Māori Girls' College stayed open, and the board of proprietors and board of trustees were working intensively together on their separate submissions, Dr Irwin said.
Both boards were meeting together weekly to create the strongest possible case to present to the minister, she said.
"We have until 11 September to make that submission. We are working with the board of trustees, we are working with our stakeholders, and we are working to get that submission ready and in a very strong position by then.
"So part of our submission will be to ask the Crown to take a whole-of-government approach to the work that it is doing in viewing Turakina's future.
"[I'm calling on] any stakeholders who have a vested interest in Māori youth to be the best they can be, to contribute to the nation-building of Aotearoa to stand up and help [us]."