Ballooning numbers of preschool children are being taught at home by under-qualified grandparents and nannies, prompting fresh concerns about the quality of taxpayer-funded early learning.
In just 10 years, the number of children enrolled in at-home care has doubled to 32,000.
Seventy per cent of those are in "standard" services, meaning their carers can be unqualified as long as they are supervised by a teacher who visits once a month.
Au pairs, grandparents and stay-at-home mums are all among those being paid from the $1.5 billion early childhood education (ECE) budget - which the architect of the 20-hours-free policy, former Labour Party education minister Trevor Mallard, says was never its intention.
"We always worked on the basis that we were heading towards a fully qualified workforce and 20-hours was part of an integrated deal to have quality," Mallard said.
"I'm not saying that grandparents can't look after grandchildren but they're not professionals or trained and don't think it's the role of the state to be paying people who don't have the training."
The Labour government brought in 20-hours free ECE for three and four-year-olds in its final term. When National was elected it kept the policy, but cut the move towards a 100 percent qualified workforce, instead aiming to have 98 percent participation by 2016.
Revelations about the number of children in unqualified settings follows years of concerns about quality in the wake of the rapid growth encouraged by the policy, including a report just this week that found a quarter of centre-based teachers wouldn't put their own kids in the centre where they worked.
The homebased sector has long been singled out as an unknown, with a 2011 government taskforce labelling homebased care "deeply troubling". That prompted education minister Hekia Parata to announce a review, with the ministry condemning many of the services as "private care arrangements".
The ministry told Radio New Zealand at the time that "housework was increasingly becoming part of home-based early childhood education, au pair services were growing rapidly, and some organisations were actively recruiting informal arrangements."
However, the review was later scrapped, with the minister saying it would be covered instead by a funding review, a review of information systems and a working group. Internal documents then revealed that homebased ECE was also considered critical to meeting the 98 percent participation target.
President of the Home-Based Early Childhood Assocation Evan Kidd said some in the sector would have welcomed the review, as it was well known that quality was an issue.
"We advocate for a level of education for all educators but there are a lot of services who have chosen not to go down the qualification path," he said. "There is definitely room for improvement and we need to push for that."
Mr Kidd said currently, the difference between the "standard" funding rate and the "quality" rate - which requires educators to have at least a Level 3 certificate - was not enough of an incentive.
He said there also needed to be a way for educators to study while they worked, which was way the association partnered with the Open Polytech.
The definition of "quality" is frequently argued about in the sector, however teaching fellow Judy Layland said at the very least, quality education meant using the curriculum, Te Whaariki. That was also required under ECE regulations.
Peter Reynolds, the head of the Early Childhood Council, which mainly represents centres, said there was no way many in the homebased sector could be considered knowledgeable about the curriculum.
"If a German student arrives in the country and within 24 hours is proceeding to teach, they wouldn't know Te Whaariki if they fell over it."
He said labelling home-based as "teacher-led" was mislead parents, who often didn't know their educators were not qualified. "It creates an unequal playing field," he said.
The General Manger of Au Pair Link, Casey Muraahi, said she thought unqualified educators could bring just as much to the table as qualified teachers.
"We do three-day workshops with our Au Pairs when they arrive. They can offer amazing opportunities for these children if they get the right support," she said.
Ms Muraahi said the amount of housework an Au Pair did was "no more than what teachers did in a centre." Au Pair Link's website advertises that Au Pairs will get children up, put them to bed, do the washing, change clothes, bottle feed and prepare meals.
Green Party MP Catherine Delahunty said the rapid rise of homebased services clearly showed a review was still needed.
"The numbers of unqualified staff is concerning. Is this care or education?" she said.
Early childhood lecturer Jenny Ritchie, from Victoria University said there was also a major lack of research on homebased care.
"And yet all these children are trusted to private homes with minimal vigilance. I think really good quality homebased can be lovely - with qualified people, small ratios, beautiful settings... but it's dangerous to have unqualified people in a home with no support on site."
The Ministry of Education said it was important for families to have options to choose from, and many parents preferred home-based settings.
It said the home-based working group had made a number of recommendations about how to improve the quality of homebased ECE and it had begun implementing those.
Teaching at home
• Home-based early childhood education involves small groups of children - a maximum of four - learning at home with an educator.
•Up to 20 educators, and 80 children, come under the supervision of a co-ordinator (a qualified ECE teacher) who must check in once a week and visit once a month.
•There are two types of home-based ECE: quality and standard.
•Quality means all educators must have at least a Level 3 qualification.
Standard means no qualification is required.
•Grandparents are allowed to become educators but cannot live at the same address as those they care for.
•Any home-based educator has to deliver the Te Whariki early-learning curriculum, have a first-aid certificate and be police-vetted. Their house has to meet health and safety standards.
•Home-based care is funded by the Government at a maximum of $9.27 an hour per child.
•There are 32,000 youngsters in home-based care, compared to 113,000 in "educare" centres, 25,000 in kindergartens, 13,000 in kohanga reo and 11,000 at Playcentre.
Kids thriving in lessons at home
The first experience mother-of-two Rohani Alexander had with home-based education wasn't a good one.
"An educator came to talk at playgroup and said, 'You could do it too'," she said. "I thought, just because you have kids doesn't make you an early childhood expert."
But Mrs Alexander persisted because she wanted her first child, Elsie, to be in a small group. She visited service after service until a friend told her about a boutique provider called The Nest.
"It just clicked. The educator had worked in a centre previously and was fully qualified. We didn't want to leave her when we moved away from Napier."
But they had to move, and so Mrs Alexander went through the same process in Hamilton to find a qualified carer.
"I met a lot of educators who were just doing it because they were mums with small children, but for me it was too important," she said. "I wanted someone who knew the curriculum, who knew the difference between care and education."
Now, a second daughter, Sidney, is also in home-based care. Elsie, 5, starts school on Monday.
Mrs Alexander says she tossed up whether to put Elsie in kindergarten to prepare for school, but in the end decided her daughter was outgoing enough not to be disadvantaged.
"All the signs so far are that she's going to thrive."