All murder cold cases reopened in NSW

About 500 cold case homicides in NSW dating back four decades will be reopened and re-examined with fresh eyes and cutting-edge technology as police attempt to catch the killers.

The first 17 cases are already being re-investigated after the state's homicide squad began assessing unsolved matters under a new framework for prioritising them.

Squad commander Detective Superintendent Scott Cook says specialist detectives from across the force will conduct formal case reviews.

"While the unsolved homicide unit is a finite resource, the NSW Police Force has a wealth of investigators whose skills can be harnessed to increase our capacity to put fresh eyes on cold cases," Det Supt Cook said in a statement on Monday.

The "rolling reviews" will also strengthen the relationship with victims' families, he added.

"We are committed to ensuring the most effective and efficient allocation of resources in order to maximise our capability to provide justice for victims and answers to their families."

The review team will look at potential witnesses, previous lines of inquiry and utilise new technology where possible.

"Things change over time and that means we have to go back and apply those changes - technology particularly - to what we've got," Det Supt Cook told 2GB radio.

The request for "fresh eyes" to examine the cases came from victims' families who also told Det Supt Cook they wanted more frequent contact with investigators.

"I've given an undertaking to victims that no case will be forgotten in NSW and just because it's been there for a decade or two doesn't mean we stop looking," he said on Monday.

The unsolved homicide squad was set up in 2004 and has so far solved more than 30 cases. A further five are before the courts.