The government has refused to fast-track a review of core early childhood education rules despite being told they might not be fit for purpose.
A Cabinet paper shows Parliament's Regulations Review Select Committee told the government in September it was not confident the regulations covering minimum space and staffing supported children's health, safety and wellbeing.
The committee also warned it was not confident the rules had been created appropriately.
It recommended the government review the regulations earlier than its current schedule of late 2023.
The interim finding followed a complaint the committee heard in August from early childhood teachers who said the minimum staffing and space requirements were not based on any evidence and were unsafe.
The Cabinet paper shows the government decided changing the schedule for its early learning review would disrupt work already in progress and would be expensive.
Reviewing the two areas of regulation in their entirety would be a significant task that would have a big impact on the rest of the work, the document said.
"The sector has indicated that teacher supply is already a concern based on current settings. Improving ratios on a faster timeline than that set out in the Action Plan could exacerbate pressure on teacher supply. Services could therefore struggle to employ enough teachers to meet minimum requirements for qualifications and adult-to-child ratios," the paper said.
"The phased timeframes of the Action Plan are also intended to manage the associated fiscal costs. If these changes are brought in at the same time as planned changes to teacher qualification requirements and improvements to teachers' salaries, the associated cost would increase significantly," it said.
The paper said the regulations included much more than the areas covered by the complaint and covered aspects of early learning such as qualification requirements and service size.
The rules require 2.5 square metres of clear space per child inside, and five square metres outside.
Centres must have one teacher for up to five children under the age of two, one teacher for up to six children over the age of two, and for more than six over-twos a ratio of at least one to 10.
One of the people who took the complaint to the select committee, early childhood teacher Susan Bates, said she was disappointed but not surprised the government would not bring forward its review.
"There's nothing in that government response that mentions children's wellbeing or the cost to children. They're talking about the cost to the sector and the cost to corporates and the cost of having to go to Treasury for more money but no-one's talking about the cost to children and that's what we see every day," she said.
Bates said the complaint was motivated by concern the regulations were not supported by any evidence.
"Teachers have been telling us for years that the ratios and space per child and group sizes were a major concern for them, their health and their workload and of course for children's wellbeing," she said.