The Government has been challenged to state how many school-leavers with autism and intellectual disabilities will get the services they need from next month onwards.
Advocacy group Inclusion Ireland estimates that approximately 40% of the almost 900 young people concerned have been offered the facilities they have been assessed as needing.
In a statement, Inclusion Ireland said that the accumulated cut of 15% to disability services over the past five years and the failure to provide additional funding for school-leavers last year is putting the teenagers' families under extreme stress.
It said approximately 40% of the 878 school-leavers concerned are being offered two or three days of services per week next month, in marked contrast to the five days per week they were getting during their school years.
The organisation's CEO, Paddy Connolly, said HSE figures, which show a majority of school-leavers getting a service, do not represent an accurate picture of the real situation.
Mr Connolly urged the Government and the HSE to publish data showing how many people will receive the level of service for which they have been assessed as needing from next month onwards.
He said that some families in the west of Ireland have been offered less than 30% of what their children require.
Mr Connolly said that in May the National Consultative Forum - comprising all disability stakeholders, including the Department of Health and the HSE - advised the department that the allocation of €4m to meet the needs of school-leavers this year was "wholly inadequate".
He has called on the Government, and in particular on Minister for Health James Reilly, to deliver on his commitment to parents to find a "fair and sustainable" service for their disabled family members.
Watch a report from 22 July - Parents of children with disabilities highlight lack of day care