"Our victim has continued to scream for help and even offered her attacker her handbag, all with the hope of drawing attention to her plight while waiting for the responding police to arrive."
She managed to make it back to the bridge and clung to a rail tightly until the attacker gave up his attempts, fleeing down the footpath onto Hardley St.
Ms Southall said the victim did all she could to even the odds in her favour.
"While everyone, regardless of gender should be able to walk the streets safely, from time to time incidents of this type arise.
"If they do, people should do exactly as this woman did: she sensed something wasn't right, she rang 111 at the earliest opportunity and then resisted her attacker, screaming to draw attention to her plight."
The attacker was described as a stocky Maori or Polynesian, around 20-years-old with dark hair and an "emo" fringe with bleached tips.
He was wearing a multi-toned singlet top that went from light at the top and faded to a darker shade at the base, shorts and possibly a satchel and open-toed shoes or jandals.
Anyone with information is urged to contact the Hamilton CIB on (07) 858 6200 or Crimestoppers anonymously on 0800 555111.