AceShowbiz - Supermodel Coco Rocha once broke down in tears while on vacation after she was shamed online for using milk formula rather than breastfeeding.

Coco and her husband James Conran are proud parents to daughter Ioni, three, and son Iver, who they welcomed in April (18), and the Canadian beauty has been happily sharing snaps of her little family on social media.

However, she has also had to face the wrath of some followers who disagree with her parenting techniques - and one incident almost ruined her holiday after posting a photo of some formula she had been using for Ioni when she was a baby.

"I remember crying in the airport at Hawaii (sic) and James started helping me with what I would write (in response) to people. I was emotional about that because no one knew why I did it but thought their opinion mattered," she recalled to Fox News.

"I pretty much couldn't make milk overnight, which was quite shocking to me. My paediatrician pretty much explained to me that... she (Ioni) was pretty much really hungry. And I wasn't creating enough milk. So right away I had to make a decision about formula. Sure enough, she latched on that bottle. For quite some months, she was exclusively formula-fed."

The backlash she received was the first time Coco had been mummy-shamed, which left the catwalk star shocked at the comments left by other women.

Sadly, it wasn't the last time the 29-year-old was criticised online, but she conceded that the shaming has opened up a dialogue that "needed to be heard".

"There are still days, not so much with Iver, I would cry in the shower over my choices that I felt were right when people were telling me they were wrong. Or how people would say such nasty things. Sometimes you literally laugh at them," she sighed.