Through educational, health and care (EHC) plans the cost of support for children with special educational needs and disabilities (SEND) is met by health services and from council social care and education budgets.
But at a House of Commons debate on SEND funding it emerged that health organisations are failing to meet the bill for all health support, which is instead having to be paid for through education budgets.
Liberal Democrat leader Vince Cable revealed that some health services are declining to even pay for wheelchairs, which are being treated as an educational cost.
Also speaking in the debate was Liberal Democrat MP Ed Davey. He said that in his constituency of Kingston and Surbiton, physiotherapy and diabetes testing are among health support that is being paid for out of education budgets.
Davey said: "Can we look at the way the NHS contributes to the cost of EHC plans?
"I have spoken to many head teachers and [children's service provider] Achieving for Children in Kingston and it is clear that the health component is coming out of the education component to deal with things such as physio, testing for diabetes, and members of staff in the classroom dealing with the child's health needs, not their educational needs.
"The bills that the NHS is not meeting run into hundreds of millions of pounds across our country."
He added that "ministers need to take action now" as "the health service is often not paying for the health part of EHC plans".
Cable, MP for Twickenham, added: "I have discovered that there are children whose need for wheelchairs, clearly a health requirement, is treated as an educational need.
"There are many such cases in which the finance sits in silos and is not sensibly dealt with."
During the debate MPs spoke of parents' struggle to access a range of SEND support for their children.
Luke Pollard, Labour and Co-operative MP for Plymouth, Sutton and Devonport, said that "parents are fighting every day" to get the SEND support their children need.
Education minister Anne Milton said that health, care and education staff need to work together to ensure children with SEND are effectively supported.
"Collaboration and joint working between health, care and teaching is what will make this work," she said.
"There will always be funding constraints, so it is extremely important that we make sure that those collaborations are in place, to stop the parents of those children from facing such a terrible fight."
Last month, health services in Sheffield were criticised by Ofsted and the Care Quality Commission following an inspection that found "unacceptable delays" in assessing and meeting health needs for children and young people with SEND.
Another concern raised by MPs was around school transport for young people with SEND aged between 16 and 18.
Since 2015 it has been compulsory for children to be educated until they are 18 years old. But councils only have to provide free transport to those with SEND until they are 16.
While some councils offer discretionary transport grants many teenagers with SEND still face huge costs or are unable to go to sixth form or a further education college, said Stephen Lloyd, Liberal Democrat work and pensions spokesman.
"That is an anomaly that the government needs to rectify," he said.
"Otherwise, thousands of disabled people aged 16 to 18, who should be going to school or in training, because that is what we want them to do, will not have that chance," he added.
Labour's shadow children's minister Emma Lewell-Buck said that some students with SEND are being charged up to £1,500 a year for their transport to school.
Milton said: "I point out to the shadow minister that discretionary bursaries are available for transport, although I know that that is an issue for some local authorities."
