Seven mothers were given the wrong baby to breastfeed in NSW public hospitals despite strict identification procedures.

Babies have been handed to the wrong mother for breastfeeding seven times in NSW hospitals in recent years, the state opposition says.

And the number could be higher but NSW Health says it doesn't have access to private hospital records.

A freedom of information request made by NSW opposition health spokesman Walt Secord revealed seven babies had been given to the wrong mother for breastfeeding in the state's public hospitals between 2011-2015.

NSW Health Minister Jillian Skinner has played down the incidents, saying they are extremely rare.

"Almost 100,000 babies are born in NSW public hospitals each year and over the past five years there were seven occasions where this error occurred," she said on Thursday.

The mistakes occurred despite mandatory ankle ID tags attached to babies straight after birth and the policy in NSW hospitals to separate mothers and newborns only for serious medical reasons.

NSW Health said the cases of mistaken identity were quickly discovered and immediate serological tests and breast-milk screening were undertaken, with mothers offered counselling.

The hospitals responsible for the baby switching accidents have yet to be named.