The spiralling costs of the Government's controversial new vetting and barring scheme are likely to be passed on to schools, heads' unions have warned.
Cash-strapped local authorities will not be able to foot all the extra bills for the Independent Safeguarding Authority (ISA) and will force headteachers to contribute, according to the NAHT and the Association of School and College Leaders (ASCL).
Paying for the new checks could amount to half a million pounds in each area, council estimates show. Local authorities making job cuts say they will be forced to employ extra staff to process thousands of new applications. Schools will have to pay if councils cannot find the money themselves.
In Dorset the costs of the ISA checks will be #163;824,473 over five years. Heads will be charged administration fees if the additional ongoing costs of #163;28,000 a year cannot be found from the council budget.
But ASCL and the NAHT said local authorities were creating the problems themselves by forcing schools to complete unnecessary checks on staff - for example the replacement of all Criminal Records Bureau forms every three years, something the Government has advised against in new guidance.
The ISA checks will cost #163;36 per person. The NAHT said it had heard of one authority planning to charge a #163;44 administration fee. The union estimated that the average cost of the new system will be #163;30,000 for every school.
"If councils didn't operate in this way they would save money and they wouldn't be in the position of asking schools to pay administration fees for the ISA checks - something that will be a real issue for headteachers," said Richard Bird, ASCL legal consultant.
"It doesn't make sense in an era of cuts to spend money unnecessarily," he added.
Tom Foster, assistant secretary in the NAHT's policy, politics and education department, said: "We think the ISA is going to cost a quarter of a billion pounds in total and this money would be better spent elsewhere.
"It is of great concern. Particularly as the current CRB system can't cope with the number of checks made and 9 million extra checks over the next five years is an additional load.
"The Department for Children, Schools and Families (DCSF) has created this climate of fear, and now it is blaming local authorities for being over-zealous. But schools are not yet clear what the safeguarding requirements on them are. Ofsted seems to be applying a different process around the country."
The new DCSF guidance, which ASCL officials helped write, was sent to local authorities last week. It says schools are making visitors complete CRB checks, even if they only have contact with children on an irregular basis for short periods of time.
"DCSF would like to make it clear that there is no pressure from government or from Ofsted to conduct such checks," the guidance says.
The Department for Communities and Local Government is monitoring the effect of the new ISA cost on councils to see if it is a "burden".