A pathologist who led body identification in Christchurch after the shootings says the process could not have been done more quickly.
He also says this was achieved with the help of a CT scanner - the first time the technology has been used in a mass casualty situation in this country.
Auckland pathologist Simon Stables led the team of forensic pathologists that examined all 50 bodies as part of the post-mortem process.
New Zealand only has eight pathologists, so they pulled in an Australian pathologist who trained in this country.
Dr Stables said they did their first post-mortem on Sunday afternoon. "So a day-and-a-half to get under way in an existing mortuary. As I say, to get all the players together, all the people involved and get an agreed process. That was an acceptable time frame. I know that the families were very keen to get their loved ones back."
He said knowing about this need, and that there was a process that must be completed, added to a pressure-cooker situation.
"The difficulty is just the pressure, which we know, we accept, that just comes with part of the job.
"And trying to get the best possible job done, and do it with the degree of detail and quality that needs to be done but still do it quickly enough that we can get the loved ones back to their families."
Dr Stables said that for the first time in a mass casualty situation, a hospital CT scanner was used, because the mortuary where they were based was near Christchurch Hospital.
"Without even opening up the body bag you can determine what the sex of the person is, is there any personal belongings there we need to have a closer look at, what are the injuries that are present, etcetera. So it provides a huge amount of information before we've even opened the body bag."
He said without the scanner, the post-mortem process would have taken much longer.
"We would have been resorting to old-fashioned x-rays, which take a while to do. You've got to get them developed and then you've got to look at them, whereas with a CT scan you can do a whole body in something like 15 minutes and then you've got those images."
Dr Stables added the other normal post-mortem option - an internal examination - were not needed in Christchurch where gunshot wounds were often clearly involved.
An Auckland pathologist colleague who was involved, Rexfon Tse, agreed the scanner was essential. "Because of the cultural issues we have to return them [the bodies] very fast and the CT scan does help us quite a bit."
The president of the New Zealand section of the Society of Pathologists, Cynrich Temple-Camp, agreed CT scans are extremely useful in an autopsy.
He said: "You can find things that you otherwise might not. For instance a body that is of unknown identity, you might be able to determine quite quickly what the gender of the person is.
"You may find things like artificial hips or other prostheses which are in the body and enable you to make an identification."
He said CT scanners are an essential tool for forensic work, and New Zealand definitely needs more.
"We rely on using the clinical scanners that are in the hospitals, but that's always difficult because there are patients that are under investigation.
"We have to clear them all out before we can actually use it. And that interferes with the normal working day."
But he said they're also very expensive, costing at least a quarter of a million dollars, and no one is holding their breath for wider use.