Mark Cahill's daughter, Abigail, was approaching her second birthday when he first noticed some unusual behaviour.
She had poor eye contact, she liked spinning in circles, and began 'losing' words that she previously had in her vocabulary.
Along with his concerned wife Claire, they brought her to their local health care provider, who referred her on to a waiting list for an Assessment of Need (AON).
Shortly after her third birthday, they got a diagnosis that Abigail had Autism Spectrum Disorder (ASD) and needed multi-disciplinary assistance like speech and language therapy and occupational therapy.
But since then, Mark feels it's been an "uphill battle" to get any kind of help for her and feels that due to chronic waiting lists for primary care assistance she is languishing on a system that no longer works.
She currently attends an "excellent" pre-school in Donnycarney with a designated ASD unit, but Mark says she is not guaranteed a primary school place there in September.
The family, who live in Raheny and also have three boys ranging in age from four months to three years, are living in an area that is seriously under-resourced when it comes to getting any kind of help.
"The system is not broken; it's non-existent. In a third-world country I could imagine, but we're supposed to be a first-world country that is thriving," he said.
"These are the most vulnerable children in our society and they have to wait three years to get any sort of public service assistance; it's unheard of. You wouldn't believe the letters I've sent into the HSE on this."
New figures released to Independent.ie have revealed a huge disparity in the number of children on the waiting list for assistance, depending on which part of the city they are in.
In the areas of Dublin north, north central and Dublin north west, there are nearly 2,500 waiting for initial speech and language assessment.
When it comes to the catchment area of Dun Laoghaire, Dublin south east and Wicklow, there is just one-sixth of that number, with 405 children waiting as of the end of December 2019.
Abigail had to wait more than two years to get into the Early Intervention Team (EIT) last May, and, apart from a few therapy sessions, has received very little assistance due to the chronic staffing shortage.
However, she will be discharged from their services when she turns six later this year and will have to join the queue for the School-aged Disability Team.
Mark has been told there's a three-year waiting list for that and says the former government's inaction on the issue is a disgrace. He is also baffled why the HSE can't divert resources from one side of the city to the other to help alleviate the waiting lists, when best practice is early intervention.
"This country is thriving, but why are our children not seeing any of the benefits? Nobody wants to tackle the problem," he said.
"It's been an ongoing battle for years. All we had was a diagnosis and a waiting list. She got a couple of speech and language sessions but there's only one OT therapist in Coolock spread across the whole of north Dublin.
"It's called the Early Intervention Team but she wasn't seen until she was five; that's not early."
He estimates his family has spent about €7,000 on getting private intervention for his daughter, but says she's being denied the help that she so badly needs.
"My gripe with this is that I've paid my taxes since I was 18 and the one time you turn to the State for a bit of support, it's not there.
"Why should I go down the private route and pay €100 for an hour of therapy for my daughter? The expenses rack up really quickly. You'd want to win the Lotto to afford to pay privately for all the therapies she needs," he said.
Newly elected TD Aodhán Ó Ríordáin (Lab) recently held a public meeting in Raheny on the issue of autism and the crucial lack of resources, and said more than 100 concerned parents attended.
"There's a huge level of exhaustion from parents trying to care for their children who feel they have to go to war with the system due to the huge lack of basic provision," he said.
In a statement, the HSE said that improving access to therapy services in primary care was a "priority" and said plans were in place for additional therapy posts in 2020.