New mother Chloe* was on her first night out with friends after having a baby when she was brutally attacked in Melbourne five years ago.

The then 22-year-old was walking home from the city along King Street to Chetwynd Street, North Melbourne, in the early hours of June 30, 2013 when she noticed a man behind her.

"I crossed the road to go over to my street and I noticed he was behind me again," she said.

"After that all I remember is being hit in the side of the head."

As Chloe passed Browns Lane, the man grabbed her in a "bear-hug" and dragged her about five metres down the lane.

A shocking image shows the extent of injuries the victim received. ( Supplied: Victoria Police )

He punched her in the head several times and knocked her to the ground, kicking her head before sexually assaulting her.

The man was last seen running south down Chetwynd Street.

No-one has ever been charged over the sexual assault, despite a call for information at the time.

Now police are offering a $500,000 reward for information to find the man responsible for the violent attack.

Sorry, this video has expired The man was captured on CCTV on King Street in Melbourne's CBD.

Investigators on Sunday released shocking images of the brutal injuries Chloe suffered and she has chosen to speak out about her ordeal to help the investigation.

Chloe said the violent sexual assault had "destroyed" her.

"I was a new mum," she said.

"I couldn't be the mum I wanted to be because I was dealing with this."

"As much as it damaged me I think it damaged me and my son's relationship."

The attack left Chloe with a broken nose and she had to have surgery on her lip.

"Every time I look in the mirror there's a scar on my face there as a reminder of what happened," she said.

'No-one deserves this'

She said after the attack she self medicated with alcohol and suffered insomnia.

"I would never wish on anyone to go through what I've gone through, ever," she said.

"No-one deserves that, no-one."

"You should be allowed to walk where you want to walk. You shouldn't have to fear for your life, or fear that someone's going to follow you and do something like that to you."

The woman was punched and kicked in the face before being sexually assaulted. ( Supplied: Victoria Police )

Police have described the man as either of Asian or Indian sub-continental appearance, of a medium build with short, black cropped hair and unshaven with stubble.

He was wearing a black top, blue jeans and an open leather jacket.

Police have also re-released CCTV which shows the man walking along King Street.

Public help needed for conviction, police say

Detective Inspector Steve Wilson said investigators believed there were people in the community who would know who was responsible for the "horrendous" attack.

He said police were interested to speak to four men who Chloe may have spoken to as she walked along Kings Street, but stressed there were potential witnesses.

"These males have got nothing to do with this assault … we would still after this time like those people to come forward if they remember the incident and hopefully this reminds them."

He said one "person of interest" had been interviewed.

Detective Inspector Wilson said investigators hope the reward would help lead to a conviction.

"We have a victim who was brutally assaulted, both sexually and physically, and is probably very lucky to still be here with us today," he said.

"I'd ask people to look at the photos we're releasing, listen to what she is saying about the impact it's had on her — then ask themselves if they're comfortable living with the information they might have about who is responsible for this crime.

"We are desperate to give this victim some closure and ensure she receives the justice she fully deserves.

"She's a very, very brave young lady to come forward."

*Chloe's name has been changed.