Some early childhood teachers fear their centres could become major breeding grounds for Covid-19 outbreaks if they are allowed to reopen after lockdown restrictions are loosened.
The government has said children up to year 10 should stay home if they can when level 3 comes in, but there will be no checks to ensure only parents who cannot work from home are sending their children to class.
Huntly mother and early childhood teacher Hannah Swinkels said any one of the 230,000 children and staff in early childhood centres could trigger an outbreak.
"They put objects in their mouths, they can spread colds very easily and it's a very hard environment to contain everything.
"My son comes home all the time with something. If I go back and my son goes back, we're doubling the exposure.
"If one child comes from a family of four, we have just essentially increased our social bubble by 4. If we care for eight children (each with four family members) that's 32 extra people we essentially share our bubble with."
Her petition calling for no schools or early childhood centres to open during alert level 3 had already attracted more than 10,000 signatures by Friday afternoon.
Swinkels said she was not willing to put her family at risk by going back to work.
"All other physical contact in other businesses is prohibited but it seems in education it's perfectly fine. So I feel like it's an exception to the rules."
Early Childhood New Zealand Te Rito Maioha chief executive, Kathy Wolfe, said it would have been easier if the Government had simply kept centres closed under level 3, but she accepted there was a need for parents to get back to work.
"This now really puts a whole lot of grey into the black and white of being in lockdown.
"So it's abundantly clear that currently both the sector and the Ministry will have to do a lot of planning and a lot of work in making sure that services can open safely."
Wolfe said it was important to note that early childhood centres had no obligation to open under level 3.
If they do choose to re-open, they may also choose to charge parents, even if they keep their children home.
"The funding that early childhood centres have received will remain in place until the end of June and is not going to be clawed back from services.
"So it's going to come down to each individual service about how they're actually going to open and operate in terms of decisions they'll make about charging parents fees."
Darfield High School principal James Morris, who chairs the Secondary Principals Council, said schools would need time to prepare.
"The big unknown at the moment is how many students are likely to turn up and parents at the moment may not even know that - depending if their work or business is able to start up again in level three."
The president of the Principals Federation Perry Rush said at a briefing this morning, Ministry officials gave school leaders a clear commitment to collaborate on the details - but the details themselves were still murky.
One crucial detail to nail down was who will be allowed to return to school under level 3.
"I certainly do not think it will be a case of 'Turn up if you feel like it on any given day', that would be too difficult to resource in a school setting.
"So I think it will be important for schools and communities to understand there will need to be a decision made about who's [eligible] to attend and who isn't."
Careful planning based on good public health advice would also be needed to provide assurance that "bubbles are set at a realistic and safe size" within each school, Rush said.
Finance Minister Grant Robertson said even if level 4 is lifted next week, it will be at least two weeks before schools can reopen and there is lots of time to work out the details.
He said he "trusted" parents to make the right decision for their children.
"Some parents will be in a position, going back to work, where they do need to make sure their children go to school.
"Of course if they can stay at home, we would want people to stay at home, then they can be there with their children.
"So we've got time to work this through."
The Secretary for Education, Iona Holstead, said every school and early learning service - and every family - would be in a different situation.
Parents who could keep their children at home during level 3 should do so to "allow schools and early learning services to provide first for families who have less flexibility at home".
"These are unprecedented times and we recognise there will be many challenges so we want to take the time to work through the details.
"We are working closely with the sector on the details around the re-opening of schools, early learning services and tertiary institutions when the decision is taken to move to Level 3. They will be fully involved in working thorough the practical issues."
Public health and safety remain "the top priority", she said.
- If you have symptoms of the coronavirus, call the NZ Covid-19 Healthline on 0800 358 5453 (+64 9 358 5453 for international SIMs) or call your GP - don't show up at a medical centre