Spending cuts mean some children are waiting more than two years for a disability diagnosis, missing out on vital therapy and support as a result.
A new survey by the British Academy of Childhood Disability (BACD) contacted 200 paediatricians who lead child development teams across the UK. More than a third of the respondents said their teams had been cut by up to 20%.
Nearly three-quarters said waiting times had increased, and 80% said they could not meet guidelines set by health watchdog the National Institute for Health and Clinical Excellence (NICE).
One paediatrician told the BBC that doctors routinely made decisions that actually delayed child care in order to meet 18-week referral targets.
The delay in diagnosis and treatment means children are left in pain, sometimes missing out on years of education.
The Department of Health, responding to the survey, said there had been an increase in the number of paediatricians employed. It did not indicate whether these doctors were specifically for children with disabilities.
A spokesperson for the Department said: “Children with learning disabilities deserve the best possible care and a timely diagnosis.
“Decisions on spending are made locally, but we are working to help join up health, education, and social care services to make sure they get the care they need as quickly as possible.”