Northern Ireland is experiencing an "autism wave" with one in 34 school-age children being diagnosed with the condition - and an expert says that services are now "at breaking point".
Research by the Department of Health shows that 8,442 school-age children were diagnosed with autism in 2017/18, with the prevalence of the condition increasing by 69% over the past five years.
In total, 2.9% of schoolchildren here have autism, with children living in urban areas 1.5 times more likely to have the developmental disability.
The Belfast Trust has the highest diagnosis of autism and the autism rate in Northern Ireland's most deprived group was 31% higher than the countrywide average.
Autism NI CEO Kerry Boyd said that a report commissioned by the Department of Education had warned of an "autism wave" in 2002.
She said: "The pressure on autism services is now at breaking point.
"In some trust areas, parents are still waiting up to two years on an assessment and support services are few and far between.
"Therefore, it is often left to the voluntary sector to fill this void, but due to the level of demand on Autism NI's services, we are already stretched to full capacity.
"Therefore, we are calling for an urgent review on autism services to address this crisis.
"Every child with autism should be diagnosed as early as possible and receive a tailored early intervention package to ensure the best outcomes for that child."
A Department of Health spokeswoman said that they were continuing to see an increase in demand for autism services.
She said: "While an additional £2m has been invested recurrently in these services since 2016 and trusts have enhanced their capacity through a range of measures, it is clear that reform is required to secure sustainable improvements in the outcomes we want for children with autism and their families.
"Following a review of children's autism services carried out by the Health and Social Care Board, plans to implement a new regional framework here are currently being finalised.
"The department is committed to tackling this issue and to ensuring that going forward we work closely with all relevant agencies to co-produce prioritised actions for delivery that are costed and fully aligned with the current autism strategy and the draft Programme for Government."
A spokesperson for the Education Authority (EA) said it continued to invest in its Autism Advisory and Intervention Service.
"Whilst it has seen a rise in the number of children being diagnosed with autism in some areas, EA continues to provide advice and support to schools and parents alongside a training programme.
"Pupil interventions and early intervention remain a key aspect of the work of the regional team."