A systemic breakdown in communication by police led to inaccurate information being provided to the public amid the Roastbusters scandal, a report into the incident says.
However, the Independent Police Conduct Authority (IPCA) said "no individual could be criticised" for that breakdown in communication.
The IPCA was called in to investigate police handling of the Roastbusters scandal after it emerged that initial information given to media was incorrect.
It looked into the adequacy of the police investigation and the handling of any complaints or reports to police from the public between 2011 and October 2013. It also looked at the information police gave to media.
It today released its findings in relation to the media, saying it could not report publicly on the police investigation as it was still ongoing.
The public's trust and confidence in police was "undermined" by the release of inaccurate information, IPCA chairman Judge Sir David Carruthers said today.
"In this instance the Minister of Police, the Commissioner and the public were advised that no complaints or formal statements had been received from any of the alleged victims of the Roastbusters and that was the reason why police had not been able to undertake further investigations or lay any charges.
"This was incorrect," Sir David said.
"Although the authority accepts that there was no deliberate decision to mislead by any police employee in this case, time should have been taken to obtain the correct details from the police files in response to questions from the media."
However, he blamed the problem on a "collective breakdown in communication as a result of other commitments and time pressures", and said no individual police officer could be criticised for the mistake.
"The provision of inaccurate information was compounded by the fact that the police did not identify or rectify the mistake themselves, despite the opportunity to do so, and instead had to admit mistakes publicly only when contradictory information was ascertained and published by the media. This resulted in a consequent negative effect on the credibility of police."
Police Assistant Commissioner Malcolm Burgess said police were on record as saying its communications could have been better and the IPCA had confirmed that.
"The IPCA points to a collective breakdown in communication due to other commitments and the pressures of time. We agree with that view," he said.
"Police is very aware of its obligation to communicate accurately to the public at all times.
Unfortunately we did not get it right on this occasion and we regret that.
Mr Burgess noted that the IPCA made no recommendations in its report.
"I can, however, say that this has been a learning situation for all staff involved and the issues highlighted in the report will be raised directly with these staff."
Speaking to reporters this morning, Mrs Tolley said that she would be making it clear to the Police Commissioner that police mistakes "really impact on victims".
The commissioner had to take responsibility for the "very basic errors", she said, because no individual at New Zealand Police had been identified as at fault.
Mrs Tolley apologised for her comments at the time that victims needed to be brave and report the crimes.
"Seeing that image of two ministers, minister [Judith] Collins and I stood here and talked to you all exhorting those young girls to have the courage to come forward, they would be treated well, but we needed the evidence.
"The effect on a 14 year-old, seeing two ministers up there saying come forward when you actually had come forward and given the evidence must have been quite devastating for her."
She added: "If I have caused any distress to that young woman, then I deeply regret it and I apologise to her."
The minister said if police wanted to have a victim-focused service, they needed to be both very careful with information but also efficient in keeping up with media deadlines.
She rejected accusations by Labour that the mistakes were the result of a tight police budget.
"All the information was there, they even had the right people at the table when they were talking.
"It's just that they didn't communicate properly, and there was no check that everyone was talking about the same issues."
Roastbusters scandal history
The Roastbusters scandal caused widespread outrage after it was revealed young men were posting videos of themselves online bragging about sexual activities with drunk, underage girls - some as young as 13.
On November 3, Detective Inspector Bruce Scott of Waitemata district said that even though police were aware of the group, there was nothing they could do until a girl was "brave enough" to make a formal complaint.
Days later it emerged a young teen had complained to police two years before, but she was not taken seriously.
The 15-year-old who went to police about the Roastbusters in 2011, said she would lay a new formal complaint after the scandal broke. She also criticised police for their line of questioning, asking her what she was wearing at the time of the assault, when she was aged just 13.
Tolley welcomes report
Police Minister Anne Tolley said that although the breakdown in communication was not deliberate, it was disappointing, and she acknowledged the apology at the time from the Police Commissioner.
"It is vital that the public, and victims, have trust and confidence in the actions of the police, which is why they must do everything they can to provide accurate information.
"I await the outcome of the IPCA's review of the criminal investigation, and acknowledge that it can't be released until Operation Clover has been concluded," she said.