New Zealand retailers are being warned about how they market bamboo products.

Four US retailers are facing fines totalling $2 million after misleadingly advertising rayon clothing as bamboo.

Consumer New Zealand researcher Jessica Williams said it is possible for bamboo to be made into fabric, but it's a chemically intensive process which results in no trace of the bamboo.

“It’s really rayon and it should be labelled as such.”

Ms Williams said retailers need to be careful what claims they’re making, as some products have been labelled as having anti-bacterial properties.

“There’s no evidence once bamboo is processed into rayon that there’s any anti-bacterial properties in the fabric itself.”

Ms Williams is telling shoppers who find fabrics claiming to be bamboo should complain to the Commerce Commission.