The bikinis, for girls as young as 6, have been on racks in chain stores throughout New Zealand this summer.
The Warehouse, Amazon and Quiksilver stock bikinis with shaped inserts which could make pre-teen girls appear more developed.
The swimwear has been condemned by Children's Commissioner Russell Wills, who said the inserts were unnecessary and sexualised young girls.
"My view is that this is padding and not lining and contributes to the sexualisation of young girls," he said.
"It contributes to the negative body image for these girls that can lead to eating disorders such as bulimia and anorexia nervosa."
After speaking with the Herald on Sunday, Wills phoned The Warehouse to demand the products be pulled from sale.
The New Zealand-owned Beach Works brand stocked by The Warehouse included triangle and bandeau halter-neck styles with removable cup-shaped inserts.
Sizes ranged from 8 to 16 years.
The Warehouse defended the Beach Works brand, which cost from just $9, describing the inserts as comfort or modesty liners, not padding.
Warehouse chief executive Mark Powell said company would never sexualise young girls.
"These bikinis have removable lining, not padding, to cater to the broad age range of our size run, which covers girls who are at very different stages of development," Powell said.
"Feedback from our customers is that they like the lining for the comfort and modesty it offers them when they're at the beach."
Despite standing by the range, Powell said on Thursday he would remove the frilly bikini, but it was still on sale yesterday. The triangle style would remain, he said.
Wills said he was disappointed with the response from the Warehouse.
"It makes sexual objects of very young girls that can lead to sexual abuse and assault."
Chris Fogarty of Billabong said its bikinis, which retail for $60, weren't designed to enhance the bust area, but had a "thin layer of foam" between the Lycra and lining.
Designers said the foam was for "modesty" and to "retain shape". A spokesperson for Roxy said padding was included to keep the top in place during movement and is also a modesty measure in case the fabric became transparent when wet.
Beachgoers spoken to this week felt the bikinis were not appropriate for pre-teens.
Shown the Beach Works halter-neck frill bikini, Auckland mum Lisa Dempsey said she would not let her 10-year-old daughter Charli wear it.
"I disagree with making children look, or want to be, older," Dempsey said.
"It is promoting the wrong image for that age."
Dempsey said the padding wasn't huge but it could make girls believe they needed it.
In 2010, UK chain store Primark withdrew padded bikini tops targeted at 7-year-olds after public outrage.
And the following year, popular American retailer Abercrombie and Fitch came under fire for a range of padded bikinis aimed at 8-year-olds. It pulled the range after parents complained and relaunched with an age target of 12-plus.
- Kirsty Wynn of the Herald on Sunday
