The accused individuals have been named on social media, and police said they are aware of the commentary online. Police this afternoon urged people to refrain from naming the men or posting personal details, as it could impact the police investigation.
One woman who spoke out about their behaviour online said in a follow-up post she had received more than 100 responses from women, men, and minors detailing similar attacks.
The woman was given permission to re-post those accusations online, providing the names of those making the accusations remained anonymous.
Many of the allegations include druggings, being chased by the men, sexual assaults and rape of people who were sleeping or passed out, and physical violence and threats.
A statement from a couple of the survivors that have been spoken to encouraged other people to come forward and speak to police.
In a media briefing this afternoon, Detective Senior Sergeant John Van Den Heuvel would not go into detail about the number of complaints made today, only that they were "a small amount".
"Whilst there has been a lot of commentary on social media and not necessarily individual complaints, so there's a lot of commentary about offending, not necessarily offending against individuals," he said.
"The allegations are extremely serious."
He would not go into detail on the number of people being investigated, but encouraged people to come forward if they had any information.
"It's too early in the investigation to comment on that."
He said police would be gathering any further complaints over the coming days and would analyse the information and conduct further investigations before progressing further.
Asked whether yesterday was the first time police were made aware of the complaints, Heuvel said: "It's difficult to say for certain because it's quite possible a complaint has been made without individuals [suspects] being identified. So part of the work we're doing today is to look through our reports to establish that."
The alleged offending was within the Wellington region, he said, and about 12 investigators were working on the case.
Police assured survivors of sexual assault they would treat reports extremely seriously.
Anyone with information which may assist ongoing inquiries are being asked to contact Wellington Police directly on 105, and reference Operation Emerald.
Survivors of sexual assault are also able to get support at Wellington HELP on 04 801 6655.