Serious developmental issues in children are being missed in New Zealand's 'B4 School' checks, the Children's Commissioner says.
B4 School is a programme that assesses all four-year-olds to see if they have learning difficulties before starting primary school.
But Judge Andrew Becroft says the number of older kids coming through the youth justice system proves the programme is failing.
"From my Youth Court experience, everything we saw in the Youth Court suggested we were dealing with quite a small group of disordered, damaged, young people and they were coming to us having missed any form of assessment or diagnosis of what was really going on," Judge Becroft told The AM Show on Tuesday.
An improved programme would give all kids a better shot, he says, and he will push the matter in a meeting with Prime Minister Bill English this week.
With about 50,000 5-year-olds heading to school each year, it could save New Zealand millions of dollars in the long run, Judge Becroft says.
"Whatever the cost is, it's going to be cheaper than the downstream costs for the education, health and criminal justice system.
"We weren't dealing with naughty teenagers, we were dealing with a very significant group of potentially dangerous young people - a drain on the health system, education system, criminal justice system and we were missing far too much of it," he says.
"I'm talking things like traumatic brain injury, learning difficulties, dyslexia, foetal alcohol spectrum disorder (FASD), autism spectrum disorder, early stages of attention deficit behaviour disorder. We need to be much more open about these things, we need to identify them so that help can be provided.
"We know of those in the youth justice system, 10 percent of them will have FASD at least, we know there'll be 30-40 percent with dyslexia or learning difficulties so the percentages are high.
"We need to see schools as an opportunity where these sorts of programmes and assessments can take place positively. I don't think by any means could it be said to be a prohibitive cost and it's good social investment," Judge Becroft says.