The new group of learning support co-ordinators will be a dedicated full-time job by a registered teacher and the first tranche of 600 will be employed from as early as 2020.
The aim is to at least double that number in order to have one in every urban school and access to one for every rural school
Ardern called the announcement "a game-changer".
"If a child needs support and is not getting it, that's not fair, and I'm not prepared to tolerate it.
"So today I want to say to parents, to kids, to teachers, to aunties, to anyone who has asked for more support for those with additional needs – we've heard you."
The co-ordinators would not only help unlock the potential of thousands of children with learning needs, they would free up teachers so all children get more quality classroom time to learn.
"A big concern I hear regularly from teachers is the amount of time they spend trying to get support for children with additional needs.
"The new learning support co-ordinators are a win-win; kids with both high and moderate needs will get on-the-ground support, parents will have a specialised point of contact and teachers will have more time to teach."
The commitment to more staff will cost $217 million over four years will be from next year's Budget and comes on top of an extra $272.8 million in the 2018 Budget operational spending for learning support.
"That is a huge investment in our first year into supporting both our kids and our teachers," Ardern said.
"One in five New Zealand children has a disability or other learning and behavioural needs and it's been too hard, for too long, for them to get support at the right time."
Learning support had been neglected for more than a decade, Ardern said.
The Government has yet to work out which schools will be the first to get the 600 co-ordinators. That will be the subject of discussion with the sector.
New Zealand First MP and Associate Education Minister Tracey Martin has been leading the work to develop a new model for delivering learning support in schools.
She was at the Labour conference for the Prime Minister's announcement.
"These co-ordinators will be a specialised point of contact for parents with someone who understands their child's unique learning needs," Martin said.
"They'll also provide expert assistance for teachers. They will work alongside classroom teachers to ensure all students with needs – including disabilities, neurodiversity, behavioural issues and giftedness – get the support they should expect."
Ardern's speech was delivered in the Dunedin Town Hall, and is the first she has given as party leader, having taken over the leadership only seven weeks before the 2017 election.
She shared many of letters she has received as Prime Minister, including one from an aunt of a boy with special needs.
It said: "We as a whānau have tried with dead ends where ever we turn so I then turn to you Prime Minister and plead for your help, he is missing out on so much and it just isn't fair. Please help us find a solution for this young boy who deserves the best chance living with autism."
Ardern said the phrase that stood out to her was "best chance."
"You may have heard me talk about my goal to make New Zealand the best country in the world to be a child.
"We simply will not achieve that unless we ensure that every single child, no matter where they live, no matter their background or ethnicity, their ability or disability, has the best education possible."
NZEI president Lynda Stuart said the announcement signalled a positive start to the week of facilitation that the union and ministry were about to embark on and was a big win for children, teachers and principals.
"It's a constructive response from the Government to the fact that the number of children with complex needs is growing while the Learning Support Co-ordinator/Senco job is currently being done on top of or squeezed in around the day job of principals, deputy principals and classroom teachers.
"This announcement potentially enables schools to release highly capable people into these roles and improve inclusion for all students. Although the current teacher shortage will make finding an additional 600 teachers challenging, the creation of this role will help support teachers and school leaders and reduce their workload — so making the job of a teacher better supported and more appealing."
Neogtiations over the primary and principal collective agreements start tomorrow and the rolling strike is still proceeding the week starting 12 November.
Altogether Autism national manager Catherine Trezona was pleased the Government had listened and was cautiously optimistic a specialised role would help address concerns at the primary and secondary level because the current education system was currently failing the majority of families with autistic children.
"We've got so many instances of children that have been stood down because there's not the capacity or the capability to work with them effectively in the school. So that's not inclusive education. Really or autistic students are not being at all well looked after in the current education system."
Some students were being expelled and then being enrolled at other schools where they could only attend for a reduced number of hours due to a lack of teacher aide support, she said.
Trezona said the organisation was delighted it was going to be a specialised role and was keen to be involved in the training of the teachers to make sure they had the skills to address the really complex learning needs of autistic children.
The boost to learning support in the 2018 Budget had funded around 1000 extra places for students with complex needs so they could get specialist support such as speech therapy.
Teacher-aide funding received an extra $59.3 million.
About 2900 deaf and hard-of-hearing students and approximately 1500 low-vision students got more help, and around 1900 more children with high needs in early childhood education would now receive support each year.
