The Greens are concerned over New Zealand's plan to attach identification numbers to young children. The political party claims that the ID numbers that will be assigned to little kids as young as three years old could be used to track and punish their parents.

As the ID system rolls out in 2014, about 190,000 pre-schoolers will be given a National Student Number. The NSN is expected to help collect information such as the children's daily attendance.

However, the Greens said that the National Government will also use the ID system to "dob in" parents whose kids don't always show up in class so their benefits can be cut.

"Answers to my written questions from the Ministers of Social Development and Education show that from next year, the Ministry of Education will for the first time track every child's attendance at pre-school and, if those children's parents receive a benefit, that information is likely to be passed on to MSD," party co-leader Metiria Turei said.

"It is completely inappropriate for preschool teachers to be used as de facto benefit police by MSD. That's effectively asking them to 'dob in' the families who know and trust them. Anything that undermines the trusting relationship between teachers and families will only do those kids harm."

Mrs Turei added that National Government is ignoring warnings from its own officials about its policies endangering children.

According to the party, some children don't attend early childhood education (ECE) because there is no appropriate ECE in their area, their parents can't afford to get them to available ECE, or their parents genuinely think that they will be better off staying at home.

"Parents who end up on a benefit for a period of time are just as capable of making decisions about what's appropriate for their little children as parents who work," Mrs Turei said. "If the National Government was serious about ensuring kids in low socio-economic areas attend early childhood education, it should establish quality services in the area where these kids live."

The NSN was first launched in 2001 to track students' progress through a National Certificate of Education Achievement.

Early childhood education providers, however, were given assurances that children's information would not be passed on.

"If there was any idea that your relationship [between provider and client] could be breached because you had to report to the Government, I think that would be a very negative thing," the chief executive of NZ Kindergartens, Clare Wells, was quoted by the NZ Herald as saying.