Education Secretary David Blunkett said more consultation was needed on the proposed bill, which would extend disability rights law to cover schools and colleges and update special needs laws. The Bill had been scheduled to pass through parliament by the end of this session in the autumn.
But Mr Blunkett said the Government remained committed to the Bill, and would publish a consultation draft by the autumn.
Liberal Democrat education spokesman Phil Willis said the Government had done less for children ith special needs than any other administration in the past 20 years.
He said: "The Department for Education and Employment can find time to issue endless bureaucratic demands and targets to both education authorities and schools, yet cannot find time for the much needed overhaul of special needs legislation," he added.
Brian Lamb, spokesman for disability charity SCOPE and chairman of the Special Educational Consortium, a coalition of 100 organisations, said the delay was disappointing. He said: "Disabled children should not have to wait much longer for the introduction of new rights to ensure they receive equality in education."