Academies are cloaked in secrecy and reduce parents' power over their children's education, according to a report commissioned by a teacher's union.
The NASUWT report says the schools give businessmen and church groups increased powers at the expense of staff, pupils and their parents.
The union, a member of the social partnership with the Government, called on ministers to halt the multi-million-pound programme because its research found no evidence that they led to higher standards. Parents have less representation on governing bodies, less ability to challenge exclusions and no right to complain to the local authority about the way the national curriculum is taught, said the report, Academy Schools: case unproven.
Academies are independent, state-funded schools controlled by private sponsors. They can set their own rules on admissions and do not have to comply with national rules on teachers' pay and conditions. Sponsors include Peter Vardy, the Christian fundamentalist car dealer, Saga, the holiday firm, and the Church of England-backed United Learning Trust.
Ministers have said academies increase parent power by giving them greater choice over where to send their children. But the study, carried out by the think-tank CatalystPublic World said oversubscribed academies choose parents rather than the other way round.
Chris Keates, the NASUWT general secretary, said: "The research found that academy school sponsors appeared generally unwilling to disclose information about the work of their schools, preventing the opportunity to have an informed debate. This is exacerbated in some schools by confidentiality clauses in staff contracts making them reluctant or fearful to talk to anyone outside the school.
"A cloak of secrecy around the sponsors and their activities simply feeds the growing unease and opposition. Those who are responsible for millions of pounds of public money should be subject to the same rigours of accountability and information sharing as other maintained schools."
A spokesman for the Department for Education and Skills called the report "selective".
He said: "It does not include any of the positive findings emerging from the ongoing independent PricewaterhouseCoopers evaluation of the academies programme, nor the remarkable achievements made by academy pupils at GCSE this year and last."
Sir Michael Wilshaw, principal of Mossbourne academy in Hackney, east London, dismissed the report as "nonsense".
He said: "The most recent results show academies are improving faster than the national rate in areas where children have been failed for generations.
"Parents want these academies. We have had 1,200 applications for 180 places. We have a higher number of pupils with special needs than the average in Hackney. That is replicated across the country."