Staffing shortages have pushed the National Forensic Pathology Service to the brink of a catastrophic unravelling, doctors say.

The Association of Salaried Medical Specialists says six forensic pathologists currently provide a round-the-clock service to police, coroners, and the public, carrying out around 1600 post mortems each year.

Between 170 and 190 of these are associated with homicides or suspicious deaths.

Executive Director Ian Powell believes there needs to be at least three more pathologists and it requires urgent action.

"It can mean delays for families, hold-ups for processing cases moving through the justice system, and there's a personal toll, the pressures it puts on specialists themselves," he said.

"They got an email in the morning about a family that can't get access to an insurance payout because there was no cause of death yet."

"That's the kind of thing that happens. Considerable disruption and stress for family members who need information."