The victim responded by kicking him in the shin with her heel.
This caused him to release his grip and she fled.
The man and the vehicle he was travelling in are not known to the victim.
Detective Carl Newton said "it's difficult to know what the man's intentions were but nonetheless this behaviour is concerning".
The offender has been described as a male Maori with a roundish face.
He has a shaven head and was wearing a dark long-sleeved top and dark pants.
Police are seeking information from anyone who may have seen the navy blue station wagon, or the man described, on Tremaine Avenue near Lynwood Close around this time.
Any information can be provided to Detective Carl Newton on (06) 213 9578 or anonymously via CrimeStoppers on 0800 555 111.