"This woman has seen something and then done something about it, thereby preventing an already traumatic incident becoming that much worse for our victim and we would to commend her for that."
The good samaritan had stayed to comfort the victim, Ms Moore said.
However, she did not accompany her to a police station to report the attack.
Ms Moore appealed for the woman to come forward to help the police investigation into the incident.
"We need to speak to her to help build up our knowledge on the offender's description. The second reason is so we can acknowledge what she has done."
To give information on the incident call Hamilton Central Police Station on 07 858 6200.
- HERALD ONLINE