Nestle says tests already completed on its new formula have not found any "safety issues", but further results are expected next week.
Parents have taken to review websites to air complaints about Nestle's NAN H.A. 1 Gold baby formula, with many saying their babies were suffering wind, diarrhoea and dark green stools, as well as vomiting, restlessness and constant pain.
Last year, the company changed its formula recipe, saying it had improved taste, texture and nutritional value.
But some parents want the product to be recalled, saying their children have suffered severe side effects following the recipe change.
"I don't know why you changed it but it's the worse formula now my baby has dark green poo, very windy, vomiting and not drinking full amounts," one parent wrote on the review website www.productreview.com.au.
One parent said their baby had been "tortured" by using the formula.
"Needless to say come the formula change he was throwing up every feed, windy, gassy and constipated he wouldn't settle at any time of day or night. He was tortured!" the parent wrote.
"Luckily I realises (sic) the cause before it caused horrible irreversible damage," another parent wrote.
Nestle said it had strict quality controls in place.
"We have strict quality control procedures in place throughout the manufacturing process to ensure our products meet the highest standards of quality and safety," the company said in a statement on Thursday.
A Nestle spokeswoman said there was nothing in the formula that should cause a problem and any health issues seemed to stem from switching formulas.
"Babies starting on the formula from scratch seem to be fine. Babies swapped from one formula to another - that's the problem," the spokeswoman said.
There are more than 100 comments about the product on www.productreview.com.au.
A spokesperson for the NSW Food Authority said in a statement it was aware of the matter, but had not received any reports of illness resulting from babies having Nestle infant formula.