Dame Kiri Te Kanawa's foundation has pulled its support of the New Zealand Opera School, held in Whanganui every January.
The loss of the funding has left Opera School chairman Donald Trott "very concerned".
"I hadn't been anticipating it, but with funding you can never be sure about what the future holds," Mr Trott told the Wanganui Chronicle.
His concerns about the school have been allayed, however, with the Freemasons Foundation stepping in to replace Dame Kiri's support.
The Kiri Te Kanawa Foundation has paid for international opera coaches to tutor at the school for the past six years. The funding has covered the coaches' fees, flights and accommodation during the two weeks of the school, plus other expenses.
In January that support saw acclaimed Welsh mezzo-soprano Della Jones and vocal tutor Cesar Ulloa, from the San Francisco Conservatory of Music, bring their expertise to Whanganui and the students who had made the grade for the school.
However, the foundation has now invested in the Kiri Programme - based at the University of Auckland - to work with promising opera singers.
Foundation administrator Paul Gleeson said the decision to end its support of the school was because its funds were needed for the Kiri Programme.
"We rely on donations and need to use our funds as best we can," Mr Gleeson said.
"We have enjoyed our association with the New Zealand Opera School but after six years we had come to the end of our commitment."
Mr Trott said he was immensely grateful to the Freemasons for filling the gap and ensuring top vocal coaches would be available to assist next year's students.
"Fortunately, the Freemasons Foundation's backing of the school means we will go from strength to strength," he said.