Schools affected by collapse-risk concrete will not have to pay for repairs out of their budgets, the education secretary has insisted.

Gillian Keegan told Sky News there will be no new money to fix the problem, but the costs will be covered by the Department for Education (DfE)..

There has been a growing row over who will pay to pick up the bill for repairs to reinforced autoclaved aerated concrete (RAAC) after the government announced last week that more than 100 schools would have to close or partially close because of the risks associated with it.

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Ms Keegan said ministers had already procured stock of portable cabins for schools that need temporary accommodation – and the DfE was paying for this “directly”.

She said: “We have eight structural surveying firms who go in and do the surveys.

“We have three portacabin providers, so we’ve laid up a stock of portacabins so that people can be prepared quickly to be able to do that if they need temporary accommodation. And we’ve also looked at a propping company that’s nationwide.

“The Department for Education will pay for all of that.”

Unions have been angered by uncertainty about which costs will be covered by government, calling for transparency on whether headteachers will be reimbursed for mitigation expenditure.

Asked if schools that are already strapped for cash will have to find more money, Ms Keegan insisted: “No, we will pay for that.”

Asked if the money will come out of school budgets, Ms Keegan said: “No. It’s coming out of the Department for Education.”

However, Ms Keegan could not say how much funding would be ringfenced towards the issue.

She said the government didn’t have the costs for this yet – but admitted it was likely to cost “many, many millions of pounds”.

On Sunday Chancellor Jeremy Hunt said he would “spend what it takes” to address the problem, but Treasury sources later said money for repairs would come from the Department for Education’s (DfE) existing capital budget.