The incident took place around 4.20pm in Centre Vale Park.
PS Bob Saxon of the Valley’s Neighbourhood Policing Team said; “Clearly this has been a frightening experience for the victim and her child, who were understandably distressed.
“Our enquiries in to this incident are very much ongoing, and I would appeal to anyone who may have been in the area and has witnessed the incident, or who has any information to come forward.”
Anyone with any information is asked to contact PC Matthew Hamilton or PC David Mayhew via 101 quoting 13170385690.
Information can also be passed anonymously to the independent crime fighting charity Crimestoppers on 0800 555 111.