A review of all NSW unsolved homicide cases would take police 900 years to complete in part due to problems finding key records and exhibits, an inquiry has been told.
The Special Commission of Inquiry into LGBTIQ hate crimes on Thursday heard it would take many centuries for investigators to clear a backlog of cases in need of re-examination even if there were no more murders in the state.
"The unsolved matters are accumulating faster than they can be solved," according to an internal 2018 police review obtained by the inquiry.
"With current capacity limitation it will take over 900 years to clear the backlog even if no further matters are added to this list.
"Given that murders will continue to occur and given that they will occur at a greater rate than they are solved, the ongoing accumulation of cases will only increase."
There had been 763 unsolved homicides in NSW since 1972, according to a 2017 police memo, but there had been no reviews of those matters since 2013.
"This has been due to significant staff shortages and the demand for resources required for current and new investigations," the memo said.
Senior counsel assisting the inquiry Peter Gray SC said it was well-known within police ranks that there were serious and ongoing problems with locating exhibits and documentary records in unsolved cases.
"Internal NSW Police Force documents have recognised the potential impact of these difficulties on the ability to reinvestigate unsolved homicides," he told the inquiry.
The commission also heard that none of the officers involved in Strike Force Parrabell, a police probe of historical deaths that were potentially linked to gay hate, had any training in bias crimes.
The officer in charge of the strike force, acting Detective Sergeant Cameron Bignell, said he didn't believe experience or training in dealing with gay hate crimes would have changed how the probe worked.
"Wasn't the overall objective ... to look at historic documentary holdings and form a view as to whether those holdings indicated the possibility of a bias factor?" Mr Gray asked.
Det Sgt Bignell said that was the job of the strike force, but he did not believe having officers with expertise in hate crimes was needed.
"What we were tasked to do in respect to reviewing case file items and completing those indicator forms, I don't think that that experience or training was necessarily relevant to conduct that task," he said.
