The number of children in Northern Ireland currently waiting for an autism assessment has increased by 280% in the last five years - and almost 50% more children are being diagnosed with the condition.
The statistics, released by the Health and Social Care Board, show that the number of youngsters on waiting lists is up from 607 in 2012, to 2,325 this year.
The figures were disclosed in response to an Assembly question from Upper Bann MLA Jo-Anne Dobson.
Ms Dobson said she was shocked at the dramatic rise and said the figures showed that the crisis engulfing our hospitals had now spread to autism services.
The Ulster Unionist health spokeswoman conceded that part of the 280% hike was due to an increase in the number of referrals, but warned: "Demand is now far outstretching capacity in the local health service."
Ms Dobson emphasised the importance of resolving the crisis, saying: "It is widely accepted that early intervention is far more cost-effective, but even more importantly it is beneficial for young people.
"Receiving a timely diagnosis can enable parents to better understand their child and ensure that they have access to crucial help and support."
One charity said the waiting times were only the "tip of the iceberg", and condemned massive inequalities within Northern Ireland's autism services.
Kerry Boyd, director of development at Autism NI, confirmed that in some cases children were being kept waiting for nearly two years.
"According to the children's care pathway, all children waiting on an autism assessment should be seen within a 13-week period," she said.
"However, through Autism NI's helpline, regular contact with families and recent research, we are recording that the vast majority of children are waiting over a year for diagnosis and in some cases up to a period of 20 months."
Despite efforts by all of the health trusts to carry out more assessments, the unprecedented demand for the tests increased by 17% last year and the upward trend has continued into the current year.
Limited availability of skilled staff for temporary posts has been blamed for the problem.
Discussions are currently taking place to allow trusts to share workloads.
An additional £2m investment made this year is currently being utilised to recruit permanent staff and it is hoped that this will play a key role in improving waiting list management.
Ms Dobson welcomed Health Minister Michelle O'Neill's apparent agreement that the current situation was unacceptable, but said: "It will take much more than sporadic funding allocations to get on top of the spiralling waiting lists."