The incident took place in the same hospital that was thought to be involved in a baby switch 25-years-ago that only came to light in January after a woman donating blood found she had a different blood type to her parents.
A DNA test later confirmed that she was in fact not related to them.
The latest baby switch that happened on Thursday in the LKH University Hospital in Graz was the result of a nurse placing the babies into the wrong cribs.
The error was only realised when a mother who had given birth to a baby boy went to wrap her child up before breast-feeding and noticed that ‘he' was now a ‘she'.
“The babies were unfortunately laid down into the wrong beds by the supervising nurse,” said the hospital's Operations Director Gebhard Falzberger, adding that the mother of the boy noticed the switch almost immediately.
As one of the mothers suffers from a chronic infectious disease, one of the switched babies had to be vaccinated, although the hospital said this was a precautionary measure and the chances of infection were “highly unlikely”.
The hospital also said that the mix up would have eventually been picked up during one of the twice-daily checks carried out by nurses, who check that information on the tags given to babies after they are born corresponds to the mother they are with.
Following the revelations that a baby-switch may have taken place 25-years-ago, the hospital posted a message on their website earlier this year that said that due to these checks the probability of babies now being switched at birth in hospitals “is generally very low".
After the hospital offered DNA tests to women born between October 15th and November 20th 1990 in LKH Graz, around 30 people have come forward but so far no DNA match has been found.