The 14-year-old was sat in the park at the bottom of Minerva Way, behind the play area, at about 8pm on Sunday (September 18) when the man approached her from behind.
He took hold of her arms, pulled her to her feet and turned her around to face him, at which point she kicked him and ran off.
The man was white, aged between 25 and 40, of stocky build, about 6ft and had short, dark hair.
He wore a black hooded top with the hood up, dark trousers and smelled of aftershave.
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Officers would like to speak to anyone who witnessed the incident or who has any information about it.
Witnesses or anyone with information is asked to contact police on 101 or Crimestoppers anonymously on 0800 555111.