High Street chain Primark says it regrets upsetting a mother who says she was told to use a changing room or leave the shop while breastfeeding.
Aimee Edwards, 24, of Bridgend said she was issued with an "ultimatum" in a Swansea branch of the store.
Primark said the supervisor's intention was to offer Mrs Edwards assistance and that it regretted any upset.
It said customers were welcome to breastfeed in its stores and it would remind staff of company policy.
Mrs Edwards, a mother-of-four, said she was feeding her four-week-old son George when she was approached by a member of staff.
"A woman shop assistant said if I wanted to breastfeed I had to go in the changing rooms or leave the store," she said.
"She said it was offending other customers, but there were hardly any other shoppers near me.
"I thought she was joking at first as I have never had a problem in any other shop before."
Mrs Edwards was shopping with her husband Ben and their children Ruby, three, and Morgan, 20 months, when baby George needed feeding last Friday.
"It's natural for a mum to feed her baby," she said.
"I was with my daughter and I want her to grow up thinking it is a natural part of life...
"I think it's disgusting that I was doing something natural and I was faced with an ultimatum."
Mrs Edwards added that she had not received a personal apology from Primark.
A Primark spokeswoman said: "A supervisor in Primark Swansea approached a customer who was breastfeeding in the store and offered her the use of a fitting room cubicle which she felt would be more comfortable and would afford some privacy.
"Unfortunately, she inadvertently caused offence to the customer who mistakenly perceived that she was not welcome to breastfeed in the store."
The spokeswoman said customers were welcome to breastfeed in the stores.
"If any customer requires privacy for this purpose, every effort will be made to accommodate this request where possible," she added.