She told The Independent: "It basically said thank you for your response, but it's not appropriate for nursing mothers to bring their babies, we will organise a separate meeting for mothers of babies.
"I was absolutely dumbfounded - I couldn't believe it at all, so much so that I actually had to go back and check the e-mail word for word to make sure I wasn't mistaken."
She said she became angry however after speaking to others about the e-mail, although she admitted she was also amused by the "blunder" - adding the "irony is unbelievable".
Dr Lesley Taylor, who runs Supporting Public Breastfeeding in Scotland, was one of dozens of a number of NHS workers invited to the event next month.
She said those who asked if they could take their nursing child were told the venue could not "accommodate" breastfeeding and were asked not to bring their children along, The Scottish Sun reported.
Scottish Labour MSP Elaine Smith told The Independent she hoped breastfeeding babies would now be welcome in the "main auditorium" of the conference following the complaints.
She said: "I think it's astonishing that in the first place organisers of a conference on breastfeeding and breaking down the barriers on breastfeeding thought it was appropriate to bar breastfeeding mums and babies from the conference.
"I'm pleased that the decision has been overturned because it made no sense at all and I trust that any breastfeeding babies who turn up will be more than welcome to be in the main auditorium."
A Scottish Government spokesman said: "When Scottish Government officials began planning the conference the number of mothers with babies planning to attend the event was underestimated.
"Consequently we have already arranged for an extension to the baby changing facilities, and a quiet area for mothers and babies to ensure that all who wish to attend can."
Breastfeeding in public has become a subject of strong political debate in recent months in the wake of a number of comments made by politicians and public figures.
The exclusive Claridge's hotel meanwhile was widely criticised last month after a woman was asked to cover herself with a "ridiculous shroud" while breastfeeding her three-month-old daughter.
Louise Burns said she burst into tears when staff members at the five-star venue asked her to cover herself and her baby with an oversized napkin in order to avoid "causing offence" to other guests.
Also last month, Ukip leader Nigel Farage said breastfeeding mothers should "sit in the corner" rather than feed their babies in an "ostentatious" way, while London Mayor Boris Johnson said breastfeeding mothers "can do it in a sort of discreet way."
Murrayfield chose not to comment when approached by The Independent.
- Independent