At least half of children aren't getting all the help they need to make the "critical" move to school, a government study has found.
An Education Review Office report said half of early childhood education (ECE) services and a third of schools were not supporting pupils well enough to ensure the jump to primary was a "positive and rewarding experience".
"Effective transitions are critical to the development of children's self-worth, confidence and resilience, and ongoing success at school," it said.
"ERO found considerable variability in how well services and schools supported children to transition to school, particularly children at risk of poor educational outcomes."
Specifically, it said unsupportive ECE services were failing to assess and communicate children's learning properly with schools.
Poor-performing schools were criticised for having rigid systems where the child "had to be ready for the school" rather than adjusting to suit the child.
The report, which surveyed 100 schools and 374 ECE services, looked at children's experiences during the transition.
The ERO's manager of evaluation services, Stephanie Greaney, said the best ECE services were the ones that recognised it was a big deal and supported parents with building relationships with the new school.
"They did special things like a board of pictures of children who had left, or would encourage the sharing of portfolios with schools," she said.
"The best of those were where the information provided showed children's learning - whereas others just had lots of pictures of activities but didn't show progress over time."
Ms Greaney said good schools talked extensively with parents, and were flexible.
Less-responsive schools only gathered formal data such as date of birth, ethnicity, and siblings at the school.
Successful environments also had teachers who understood the curriculum and were culturally supportive. Maori and Pacific children were disproportionately over-represented in the least-supportive services.
The president of the NZ Educational Institute union, Louise Green, said the poorer results for ECE services were the consequence of not having 100 per cent qualified and registered teachers in the workforce.
"Implementing the curriculum is a skill. As is assessment that identifies the learning - it's not just a child sitting in the sandpit, it's asking what does the sand feel like or what they're making."
Principals Federation head Denise Torrey said it was important for kids to feel connected and for schools and ECE services to share information.
However, she said, sometimes it was difficult - her school, for example, had 31 different feeder services and it was a lot of work to ensure it was engaging with all of them.
Both the union and the federation agreed with the report recommendations that schools and services review their practices and work on relationships, and that the Ministry of Education consider ways of supporting teachers to work together.
Buddy made big transition happy one
A buddy system helped Tahlia Rehm settle in to school so well that now her little brother is itching to join her.
Tahlia, who attended Mangere Bridge Kindergarten, had an older student come to meet her regularly before she transitioned, and continued to be her friend when she joined Mangere Bridge School.
"It was fantastic," said her mother, Vanessa Rehm.
"She already had a familiar face
so there was no worrying about who to have lunch with or anything like that."
The kindergarten, which won a Prime Minister's Education Excellence award, also provided a portfolio Tahlia had in the classroom for comfort.
That, plus three school visits and a welcoming environment, made for a stress-free transition.
"I was three weeks off having a third baby when she started so I was a bit emotional and cried on her first day," Mrs Rehm said, "but the teachers were the business and obviously knew what was best.
"Tahlia [now aged 6] is very happy and now her brother Aston  is excited to start too."
Six ways teachers can make the transition to school easier
Holding a '4-year-old' meeting to begin the dialogue with parents about transition to school.
2. ECEs staying in contact with children who have gone to school for a period of 12 weeks after they leave. These children are welcome to come back to visit.
3. ECEs making learning journals for all children approaching school which show the youngsters' developing dispositions and skills, which they can take to school.
4. Schools displaying photos of children before they start, so that other pupils know they are coming and can welcome them.
5. Schools having a formal 'buddy' system to support new entrants. Buddies are either classmates or senior pupils.
6. Organising an enrolment pack, familiarisation visits and meetings with staff all provide good information for parents.
- Source: Education Review Office