Many early childhood centres are struggling because thousands of children are staying away.
About 40,000 children - 20 percent of under-fives - have not returned to early learning after lockdown, the Early Childhood Council says.
With fewer enrolments, centres get less income and some have too few children to be sustainable.
Darius Singh of Chrysalis Early Learning Centres in Auckland and Tauranga said up to 5 percent of children might normally be away during winter because of sickness, but about 30 percent were now not coming in.
He said extra government funding provided during lockdown shielded the industry from the immediate effects, but it was now beginning to cut deep.
"The expenses are the same because we still have full staff compliment, and we're still running the place, that's where the pain is really getting to us, we obviously can't sustain this.
"I think the ultimatum is closure for a lot of centres. This is where we just hope that the confidence in the community just picks back up."
Singh said many families who had lost jobs were unable to afford the fees, but others were keeping children home over fears about Covid-19.
The most frustrating thing, he said, was that every quarantine breach added to those fears.
"It's like fighting an emotion that no one can pin down, it's fighting an enemy you can't see, and it's not Covid we're talking about it's the emotions of the whole community. We don't know what to do with that. How do you improve that?"
Singh's Early Learning Centres are offering heavy discounts, which he hoped would help struggling families stay enrolled, but he said that could not go on forever.
Sarah Alexander from ChildForum said for some centres the drop in attendance might not be temporary.
"For some services parents have lost their jobs, and it's unlikely that the demand for childcare will return to normal unless the parents have jobs again, and are earning at similar levels to be able to afford care."
Alexander said though centres might be facing closure, there was still plenty of work for teachers elsewhere.
Early Childhood Council chief executive Peter Reynolds said the average of 20 percent of children away was not spread evenly - some centres had a lot more missing, and there was no clear pattern.
He expected some would be forced to close before the end of the year.
"Some centres are struggling to get children back, and are doing what they can to try and convince parents. Both parents and children can feel very confident that returning to an Early Education and Care Centre is a safe place to be."
Reynolds said parents should talk to ECE centres openly about any concerns, should visit to see their safety measures themselves - or even ask for learning material to help keep their children learning, if they are at home.