Some early childhood centres are repeatedly falling below the minimum staffing levels designed to keep children safe, teachers say.
They told RNZ News that in some instances the failure was deliberate, with non-teaching staff logged as being "on the floor" working with children even though they were not.
"We're supposed to be one-to-five ratio in under-twos, more often than not we would be running at 35 children in a room that was licensed for 30 with five teachers," a teacher said.
She said the centre's van driver and cook would be counted as teaching staff, but they were not working with the children, and the environment was not safe.
Susan Bates, head of the Teachers Advocacy Group, a support group for early childhood teachers, said such stories were not uncommon.
"I was recently with nine toddlers for quite lengthy times of the day as a reliever," she said. "I've been outside with 20 children, older children, and more, and I hear this a lot from teachers."
Ms Bates said in some instances teachers were being told to falsify records so there was no evidence that a centre was under-staffed or had failed to make mandatory health and safety checks.
Sarah Alexander from the organisation Child Forum said some services did not have a good understanding of how the government's teacher-child ratios worked.
"For example, it can be common for teachers who are not actively working with children, who may be in the office or doing other things, to be counted within ratio and legally, that's against regulation."
The ratios required one staff member for every five children under the age of two, and one staff member for every ten children over two-years-old.
Te Rito Maioha Early Childhood New Zealand represented about 450 early childhood services.
Its chief executive Kathy Wolfe said she was aware of reports of services operating with too few teachers.
"They're alarming, no matter whether they're rare or not," she said.
Ms Wolfe said early childhood services were struggling because their per-child government funding had been effectively unchanged since 2010 and they needed more support from the government.
Education Minister Chris Hipkins said the Education Review Office and the Education Ministry were good at spotting problems in the early childhood system but they needed more ways of intervening in poor quality services.
The Education Ministry's deputy secretary sector enablement and support, Katrina Casey, said meeting the teacher child ratios was a legal requirement for early childhood services and the ministry would investigate alleged breaches.
"A breach of those requirements would be totally unacceptable. If anyone has any information about a specific service falsifying its records or breaching its licence in any other way we urge them to provide us with that information," Ms Casey said.