One of the nation’s top cops has opened up about the moment that’s haunted him over his 31-year career.

In a raw interview with Ray Hadley, NSW Police Commissioner Mick Fuller addresses the significant mental health challenges facing the force.

His comments come as three officers, who attended a horrific crash at Orchard Hills in September, still haven’t returned to work.

Commissioner Fuller says they’ve come a long way in dealing with physical injuries, but more needs to be done to support those battling mental illness, particularly Post Traumatic Stress Disorder (PTSD).

“I’ve got to keep talking about it on the radio.

“I’ve got to keep talking about it to the troops to try and make it less of an issue putting your hand up and saying, ‘Look, I’m not well’.”

The state’s top cop shared his own personal struggles brought on by the job.

“It was having to deal with the people alive, that death impacted on, that I found the hardest. Whether that was a cot death, right through to a homicide.

“I always found dealing with the family members a very stressful thing and I still do to this day.”

Commissioner Fuller highlights one incident that’s always stuck with him.

“We had one particular case a long time ago where a man died in a terrible accident.”

Click PLAY below to hear the Commissioner’s story