Several women have been groped by an assailant on an e-bike while walking along picturesque beach tracks.
Six women reported they were attacked while walking and jogging on trails on Sydney's Northern Beaches since the beginning of October.
Between October 7 and 8, two women reported they were approached by an unknown person in Narrabeen who sexually touched them.
Another woman reported she was targeted with sexual comments while jogging.
All three women said the man, described as Caucasian, in his 20s and around 175cm tall with dark brown hair, then rode away on his e-bike.
He was wearing black pants and a blue shirt.
NSW Police have appealed for information after the alleged spate of incidents
On Monday, detectives received a further report from a woman who also said she was touched by an e-bike rider of similar appearance on October 1.
The State Crime Command's Sex Crimes Squad began assisting a strike force investigating the incidents.
Police received a further report on Monday after two women who were walking along Narrabeen Lagoon between 5 and 5.30pm said a younger boy, aged 16 to 18, riding an e-bike sexually touched them before riding off.
He was described as being of Caucasian appearance, around 175cm tall and wearing a bright yellow top with green on the sides, black pants and a round black helmet.
Police are still investigating whether the incidents are linked.
Detectives have requested anyone with information, or footage of the incidents or perpetrators to contact Crime Stoppers on 1800 333 000.