By Simon Wong and Kate Harley
Prime Minister John Key says Police Minister Anne Tolley is "absolutely right" to ask the Independent Police Conduct Authority investigate the police handling of the Roast Busters investigation.
The minister made the unprecedented move to write to the authority today and says she is disappointed the full facts weren't available to her.
She was only told last night by Police Commissioner Peter Marshall a formal complaint against the group had been made after previously being told such a complaint did not exist.
"It's not a great situation when you leave your minister in the dark and that feels like the situation we've been in," Mr Key says.
He says the police handling of the investigation so far is "on the surface very disappointing and frankly not good enough".
Parents will want to know if their daughters make a complaint to police it is taken seriously, he says.
After calling a meeting with Mr Marshall at the Beehive, Ms Tolley asked for particular focus to be put on the questioning of a 13-year-old girl, who in 2011 went to police claiming she had been raped.
Police revealed this morning four girls have complained about the Roast Busters, despite earlier claiming no victims had come forward.
Three complaints were made in 2011, and one was made last year.
READ MORE: Police apologise to alleged Roast Buster victim
3 News reported last night the girl was asked to re-enact what was done to her with dolls, but was told her evidence was not enough to lay charges. She felt police inferred that she was "asking for it" due to the clothes she was wearing.
Ms Tolley doesn't believe this is acceptable.
"Parents of young girls need to have confidence that complaints to police about sexual assault are investigated thoroughly and appropriately," she said.
"The IPCA does have the power to carry out an independent assessment of the details surrounding these events, and I believe this is the right course of action to ensure the public has confidence in the police on this matter."
She said as minister she cannot delve into the details of the investigation but she has been given assurances by Mr Marshall that his staff did the right thing.
"This morning the Commissioner has again assured me that this inquiry has been thorough, and that there was a comprehensive investigation into the victim’s complaint.
"However, I have made it clear to the Commissioner that I am disappointed that the full facts have not been available to me or to him."
She says although she doesn't expect to be told the details of the operation, she does expect police to be talking to each other.
She has also urged the groups' victims to speak up.
"I would again urge any young women who have been affected to come forward and talk to police as a first step in gathering evidence which can be used to bring people to justice."
Police admit misleading the public
Mr Marshall defended the handling of the first complaint, saying it was dealt with formally, taken to its "natural conclusion" and investigated thoroughly.
"It was investigated to the extent that the nominated people were interviewed and there was not the evidential threshold in relation to that particular matter. That unfortunately happens from time to time."
He says police are keen to make progress with the other three girls, who were reluctant to make a formal complaint, and parents of two of the alleged victims had suggested police not contact the girls again.
"We are working towards speaking to them again," said Mr Marshall. "It's entirely their decision. We want to provide a very safe environment for them."
Mr Marshall says there needs to be a complainant willing to give evidence, but guaranteed the people involved will be dealt with appropriately.
"That is the crux of the matter. We're in the business of finding out what these young men were up to."
Police only get one shot to convict someone of a crime, he said.
"If a person is discharged by a court, judge and jury then that charge cannot be re-laid. So we want to do it carefully, we want to do it appropriately. We've only got one chance at this."
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More complainants coming forward could form a pattern of behaviour among the group and more evidence, he says.
Mr Marshall says he told Ms Tolley "within five minutes" of learning there had been a formal complaint laid, as revealed by 3 News last night.
He says the public were misled when they were told there was no formal complaint against the Roast Busters.
Waitemata police district commander Superintendent Bill Searle apologised on Firstline this morning to the first complainant for the stress caused.
Mr Marshall has now also apologised.
"I extend that same apology. We're in the business of not upsetting victims. She was a legitimate victim who came to police and I didn't know and Supt Searle didn't know that that formal complaint had been received when Supt Searle was talking to media on Monday."
Mr Marshall welcomed the IPCA investigation saying it would bring a "fresh look" on how the process was handled.