The victim was walking along a footpath accessed by Ilex Way around 11.45am on Tuesday (December 18) when she was approached by a man from behind, police said.
The man pushed the victim into a bush and sexually assaulted her before riding off on his bike, confirmed police.
Detective Inspector Sally Arbuckle said: “This was an isolated and unprovoked attack and we want to hear from anyone who could aid our investigation.
“The suspect smelt strongly of aftershave, had dark coloured eyes and was wearing a blue hooded top.
“We would like to speak to anyone who witnessed a man matching this description in this area either before or after the offence occurred.”
You can report information online or by calling 101 quoting 532 of 18/12.