A man has been arrested for punching a five-day-old baby in the face because he thought the girl was a toy.

Mother Amy Duckers had taken her newborn Elsie Rose, who weighs only 3kg, out of the house for the first time to shop at a Manchester supermarket on Monday night when the attack happened.

The pair were inside the UK shops when a stranger ran to the pram and lashed out at Elsie with a vicious punch, only to recoil when the infant wailed in pain.

The 63-year-old man then told Ms Duckers he thought the baby was a toy.

“We all heard the punch land on my little baby. We didn’t react at first as we were just so shocked. Then I just screamed,” Ms Duckers told the Manchester Evening News .

“He could easily have killed her.”

Amy Duckers was taking her baby out of the house for the first time when she was attacked. (Photo: Facebook)

Apparently the attack was triggered when a neighbour came over to see the newborn child and said “have a look at this lovely baby”.

The man then rushed over and punched the child in front of Ms Duckers and her other child, seven-year-old Libby.

“We were mortified, my daughter was screaming thinking he had killed the baby,” Ms Duckers said.

Elsie Rose was treated at Wythenshaw Hospital overnight.