Dozens of staff have written to the chairman of governors at a school to oppose academy conversion proposals.
More than 70 teaching and support staff are believed to have expressed concern over proposals to convert Rushey Mead School, in Leicester, into an academy, in letters to Ann White, chairman of governors.
However, executive head teacher Carolyn Robson has said that about half of these have been withdrawn following "reassurance" over what could happen in the future.
Academies receive funding directly from the Government and have more powers over areas such as curriculum and staff pay.
Leicester's branch of the National Union of Teachers (NUT) is strenuously opposed to the move, which it claims will "privatise" a publicly-funded site and give parents no local accountability via the city council.
The branch said it will ballot members over potential strike action in the next academic year if the proposal is given the green light.
Rushey Mead, which has about 1,350 pupils, has received a grant of £25,000 to help with potential conversion.
Ian Leaver, assistant branch secretary for Leicester's NUT, said: "Applying for a £25,000 grant ahead of any decision speaks volumes for the school's intentions.
"It's a large sum of money intended to help with legal matters concerned with conversion. Furthermore, the head has claimed the city council would like it to support local primary schools to improve and this can only be done by converting into an academy.
"On the contrary, the city council has made it quite clear that it opposes any such conversion."
In a statement to the Mercury last week, Councillor Vi Dempster, assistant city mayor for schools said she could "see no benefit whatsoever" in a conversion.
Kevin Courtney, deputy general secretary of the NUT nationally, was due to visit the school to talk to staff today.
Mrs Robson said: "The consultation process around possible conversion will involve a wide range of stakeholders including staff, parents, the community, other schools, the local authority and our young people.
"We have also begun conversations with groups of staff and individuals to explore what conversion would mean. Staff understandably want to explore any potential changes to contracts, pay, conditions and pensions, and it has been explained if we continue this process we would adopt an approach which would protect all these things.
"The school has drawn up a frequently asked questions sheet for staff where we are collating any issues or questions raised and are writing up factual responses.
"A number of staff, before knowing the details, made initial expressions of opposition, of which the governing body is fully aware, but about half of these have now withdrawn their letters, having now been reassured about the facts.
"The Academy Support Grant of £25,000 is made on the basis that the school is considering conversion. We need to access this funding so we can adequately explore the legal and HR matters."
Any grant funding spent is repayable should the school not convert.
A formal consultation is due to start in September before a final decision is made.
Rushey Mead has just undergone a £17 million rebuild under the city council's Building Schools for the Future programme to improve every secondary school in Leicester.
