The special commission of inquiry that opened in November 2022, is examining unsolved deaths suspected of being LGBTIQ hate crimes in NSW between 1970 and 2010.

Justice John Sackar, who is presiding over the inquiry has described police conduct as "unprofessional" for failing to produce documents in time.

He was due to submit his final report by August 30, 2023, but the deadline has been extended to December 15, after police delayed providing documents and the discovery of new forensic evidence.

Today Counsel Assisting Peter Gray SC, said the inquiry had partly been extended after NSW Police submitted more than 50 new witnesses should be spoken to before any findings are made.

Mr Gray said the 50 individuals have been asked to provide statements, but nearly half have not responded.

He said that since at least 2016, "serious ongoing difficulties in locating documentary records and exhibits in unsolved cases" has been well known within the police force.

This is making it difficult to reinvestigate unsolved homicides.

Mr Gray referred to a police internal document submitted to the inquiry, dated 2018, which outlined the task officers were facing.

"One internal police document in recent years estimated that if the unsolved homicide team continued to review cases at its then current rate, it would take 900 years for existing cases to be reviewed," he said.

"I note in passing that even as late as last week, in mid-September, yet more belated documentary production was still being made by the NSW Police Force.

"That production of material last week, was in response to a summons issued in August 2022, more than a year ago."

Mr Gray told the inquiry NSW Police represents itself to the community as having a "competent and adequately resourced team to deal with unsolved homicides".

He noted it was common for a coroner to refer matters to the unsolved homicide team.

"It is assumed that, when doing so, the coroner and relatives of a deceased person expect ... the matter will be considered by the unsolved homicide team within a reasonable time, and not a period of time that can be measured in centuries."

A number of high-ranking officers have been questioned at the inquiry about incomplete records, lost exhibits, and investigative failures into unsolved LGBTQI deaths