"We have large waiting lists and we're not getting to the children as quickly as we'd like, because we know early intervention works."
NZEI Tai Tokerau field officer Peter Hughes said there were around 40 members in Northland, who joined around 900 nationwide on strike.
He said the workers had been offered a two per cent pay rise on settlement, and another two per cent next year.
Hughes said the specialist workers were looking for something like a 10 per cent pay rise, to make the profession attractive.
Early intervention teacher Sharon Keto said they worked with children who had developmental, psychological, behavioural and physical needs which need addressing for the child to reach their full potential.
"We've seen when we work with teachers and whanau efforts, the children make amazing progress. We want to be able to do our jobs as well as we are trained too."
Ministry of Education deputy secretary business enablement and support Zoe Griffiths
said the ministry remained committed to progressing negotions with NZEI Te Riu Roa and APEX towards settling this agreement.
Griffiths said they value the work that field staff do and know some field staff have high workloads at the moment and they are actively working to fill vacancies in areas where there is high demand.
She said the ministry will have arrangements in place to manage urgent appointments as well as supporting schools if there are any traumatic incidents during the strike action.
"Our staff are committed to supporting children and young people they work with so will either rearrange any appointments or if it's an urgent case, our other staff will ensure their needs are met."
