Police bosses will not say what they're doing with intelligence gathered in the discredited formal warning system.
A High Court judge ruled the system was illegal, and police this week said no appeal against the judge's decision will be lodged.
But Police National Headquarters has refused to say what it will do with information in the National Intelligence Application (NIA) about formal warnings.
The union representing police officers says the system was problematic, and some warnings were issued even without a suspect admitting wrongdoing.
"I have personally had an issue with this practice. I don't think it's right," Police Association president Chris Cahill said.
Details of these warnings could be shared with other agencies for vetting purposes, affecting the warned person's job prospects.
Cahill said warnings were issued for various reasons, including when police did not believe the Solicitor-General's guidelines for prosecution were met.
"It can be that it's not in the best interest of the victim, it's not in the public interest. The problem is if the person hasn't admitted that offence," Cahill added.
He said some formal warnings had disregarded the legal principle about burden of proof: "He who asserts must prove."
Cahill understood police might have to remove details of formal warnings if people requested deletion.
A senior police source said the warnings were used as part of a broader, long-term, politically motivated trend to prosecute fewer people.
He said this trend also extended to arresting fewer people, and police custody units for holding people commonly had much smaller capacity now than in the past.
The source did not expect police to widely advertise any offers to remove formal warning data from NIA.
A formal warning was more serious than a pre-charge warning, which was in turn more serious than an informal verbal warning, of the type commonly issued on the streets with unruly people.
Police said there was no accessible data on how many formal warnings were issued, unless requested through the Official Information Act.
Asked what was happening with data about formal warnings in NIA, police dodged the question, and when asked again, said they had nothing to add.
"The common law power to use discretion and issue warnings pre-dates police systems such as NIA," a police spokeswoman said.
She said police were working to find a way of preventing the sort of situations that led to formal warnings being successfully challenged in court.
The case that toppled the formal warning system involved a teacher wrongly warned over grooming accusations.
The High Court found the warning was illegal, and should not have been given.
Apart from formal warnings, details of pre-charge warnings are also held in NIA.
Police have said the formal warning system is being reviewed, and not completely discarded.
Superintendent Iain Saunders on Tuesday said police aimed to have an updated formal warning policy in place by the end of the year.