Parents are to be given more financial control over support for children with special educational needs, in a major shake-up of the system in England.
The government says it wants to push ahead with proposals announced last year that parents should have a "personal budget" for their children.
The changes could also see fewer children in the special needs category.
Children's minister Sarah Teather said the current system was "outdated and not fit for purpose".
But head teachers' leader Brian Lightman warned: "Tightening the criteria for being identified as having a special need must not be a cost cutting exercise."
The government is setting out its response to last year's green paper on special educational needs - which warned that too many parents felt frustrated with having to "battle" against the system.
It also said that too many children were being labelled as having special needs - with more than one in five pupils currently in this category.
It called for parents to be given more control over spending the budgets available to help their children.
Ministers now want to press ahead with this proposal, so that by 2014 parents would have the right to buy in services, rather than relying on the options decided by local authorities and support agencies.
This is intended to help parents ensure a more personalised package of support for their child.
But parents would still be able to leave such decisions to the local authority if they preferred.
There will also be a push for more co-ordinated commissioning of support between education, health and other services, to reduce the risk of delays or bureaucracy.
The intention is to remove the sense of a struggle between families and support agencies over assessments and the support available.
A major change will be the scrapping of the current system of statements setting out the extra help that has to be provided for children with severe or multiple learning needs or disabilities.
A simpler system is promised with the introduction of a single assessment process, for all levels of special need, which would result in an integrated Education, Health and Care Plan.
But children who have statements are only a small proportion of children classified as having special needs.
And the green paper suggested that "too many children are being over-identified" as having a special need, with this label being applied to a very wide variety of problems.
A report from Ofsted in 2010 claimed that the special needs category was being used too widely.
Teachers' unions have strongly rejected the claim and warned of cuts to support services for special needs.
Within the school population, 2.7% of children have statements - representing those with the greatest physical or mental health needs.
But almost 18% of children are categorised in two lower levels of special need - School Action and School Action Plus - representing about 1.4 million pupils.
This includes difficulties such as persistent emotional, social and behavioural problems, communication difficulties or a sustained inability to make progress.
The proportion of children identified as having special needs, outside of those with statements, has risen sharply - up by 80% since the mid-1990s.
The green paper identified the rise in some specific areas - behavioural and emotional difficulties rising by almost a quarter in five years.
Speech and communication problems had risen as a special needs problem by 58% over the same period between 2005 and 2010.
Sense, the charity for deaf-blind children, welcomed the proposals as a way of improving the rights of families.
"Presently families are enduring a fraught and complex system and are often subject to significant delays," said a spokeswoman.
But the National Autistic Society voiced concerns that tightening the criteria for special needs could mean that more children with autism will "fall through the gaps in the education system".
Labour's spokeswoman on children, Sharon Hodgson, said that implementing changes would be difficult when councils faced budget cuts.
"Pupil referral units and young offenders institutes are full of young people who have been failed, going through their school lives with undiagnosed disorders and additional needs.
"So for the government to focus on taking arbitrary numbers of pupils off the SEN register is entirely the wrong starting point," said Ms Hodgson.
The children's minister said the changes would help remove the delays and confusions facing families who need help for their children.
"Thousands of families have had to battle for months, even years, with different agencies to get the specialist care their children need," said Ms Teather.
"It is unacceptable they are forced to go from pillar to post, facing agonising delays and bureaucracy to get support, therapy and equipment."
'Not about numbers'
She denied the government are bringing in the reforms purely to reduce the number of children recorded as having special educational needs.
"For me this is not about numbers, it is about getting the right children identified and getting the support in place. We do not have a target."
But the NASUWT teachers' union said it was not clear that the proposed changes to the system would address parents' concerns.
The NASUWT said personal budgets amounted to vouchers which were about opening up a market in the provision of SEN care, rather than ensuring children were properly catered for.
General secretary Chris Keates said: "The key message is that the coalition government is seeking to redefine what constitutes SEN, in the context of an economic austerity programme.
"This can only mean that fewer children will qualify for additional support and teachers and parents will be left to pick up the pieces."
Nasen, the association for special needs professionals, says it has concerns about the scrapping of School Action and School Action Plus and says schools will need "advice and support" in implementing this.
The proposals will be included in a Children and Families Bill announced in the Queen's Speech.