Desperate parents are begging Treasures to fix a new and "improved" nappy design which they say is causing leaks and nappy rash.
The Kiwi company switched its nappy design earlier this year but feedback from scores of parents said there were several flaws with the new design.
New mum Seanna Hislop said since the switch she'd been using nearly twice as many nappies a day.
"They just leak. The poo comes out, they get damp," a frustrated Hislop told the Herald.
A previous Treasures fan since her daughter Faye's birth, Hislop had now switched brands after finding herself having to change her baby's nappies every hour or two because they'd start to leak.
When she put Faye in a pair overnight they leaked through three layers of winter clothes onto the five-month-old's cot.
"We've had to switch to Huggies because I would wake up in the middle of the night with a screaming baby and her bed would be completely soaked through."
Hislop had also experienced the waistband and tabs of several pairs of nappies pulling when she tugged at them and Faye had begun to develop a nappy rash while wearing the new Treasures design.
The young mum wanted Treasures to recall the nappy, and offer parents who had bought the new formula a refund.
"Their whole motto is about looking after little Kiwis and they're not. It's really frustrating."
She, like many other parents, bought her nappies in bulk and now had about $100 worth sitting in her home which she didn't want to use.
The Kapiti Coast mum said her friends had also experienced the problem, and dozens of complaints left on Treasures' Facebook page echoed Hislop's claims.
"Hi treasures! See the time, it's so early ... the past five nights I have been up with my 6-month-old as she is leaking through. The only thing that has changed is your nappies," another mother wrote.
Many others also wrote to say they were upset with leakage, absorbency and red rashes associated with the new nappy use.
A Treasures spokeswoman refused to say how many complaints the company had received, but said it was a tiny portion of customers buying the new nappy design.
More than 5,500 samples of the new nappy were tested on Kiwi babies and the same amount of absorbent material as the previous design, she said.
"An overwhelming majority of consumers who sampled the new nappy told us that it was as good as or better than the previous nappy."
The company was surprised to hear of the complaints, however said they would respond to each and every one.
"As a result of consumer feedback, we will be making further refinements and enhancements to the new nappy, including to increase absorbency."
Direct questions about the possibility of a recall and refund were not answered.
The spokeswoman said instead that any parent with a complaint should get in touch with Treasures to provide contact details and send the affected nappies back for testing.