A woman raped in the early hours of Christmas Eve was waiting for a taxi when the assailant struck.
Police said last night the woman did not know her attacker.
Detective senior sergeant Andy King said sexual attacks by strangers were unusual. "It is of huge concern to us."
The24-year-old was attacked in Mills Lane, which runs parallel to Queen St, between 2am and 3am.
King said she was attacked as she made her way home from drinks with friends at a city centre bar.
The woman was waiting on Albert St for a passing taxi before the attack.
He would not reveal how she came to be at Mills Lane.
"It's pretty frightening that it can happen in such close proximity to such a busy area."
King said the woman was too traumatised for a full interview. He hoped she would up to it this week.
"The trauma is obviously extreme."
Security camera footage from the neighbouring APN building - where the Herald on Sunday, the New Zealand Herald and New Zealand Magazines are based - was taken by police to assist the investigation.
It's not the first major crime in Mills Lane.
In September last year, Austin Hemmings was stabbed to death after helping a woman as he left work.
Pauesi Brown has been charged with Hemmings' murder.
