Thousands of people from around the country have been deeply affected by Friday's brutal massacre of 50 people in Christchurch's mosques.
The psychological impacts are likely to be far reaching and long lasting.
Here's a look at the toll it is taking, what's being done and advice for those struggling to cope.
Whether directly involved in Friday's shooting or not, it's been a rough eight years for much of the city.
Thousands of people sought counselling following the devastating 2011 earthquake and Friday's events were likely to bring back the feelings and emotions for some people, said Canterbury Charity Hospital co-founder Professor Phil Bagshaw.
The Charity Hospital already had more than 30 counsellors ready to provide free help to anyone who felt they needed support dealing with the mental and psychological impact of the shooting.
"How big this will be, nobody can tell us. The experts tell me it will be massive," he said.
"What the experts say is that in quite a few people it will trigger memories and feelings that they had at the time of the earthquake. There are going to be lots [of people needing help] and it's going to go for a long time."
Bagshaw said it was important for people to realise it was normal to feel upset by the events.
"It doesn't mean you're sick or anything. If you keep on doing normal things, it helps. Don't self-medicate with drugs or alcohol. You have to talk to people - talk to friends, people you trust.
"If the feelings become overwhelming you should ask for help straight away and if you can get it within a day or two the chances of success are better."
Bagshaw said you did not need to be referred by a doctor. Anyone who felt they needed counselling could contact the Christchurch Charity Hospital on (03)360 2266 to arrange an appointment.
Christine Macfarlane, Canterbury executive member of the NZ Association of Counsellors, agreed the after-effects would not been seen for weeks or months.
It was normal in the immediate aftermath for people to find they were not sleeping or were frightened or startled easily.
But if, in a couple of weeks, people were still struggling to sleep or had a sense of fear, they should seek professional help.
There would be mixed reactions from people, she said.
"People in Christchurch know what trauma is, they know how to deal with it," she said.
But for some people the event would act as a trigger, reminding them of past experiences like the earthquake or abuse.
Most survivors would still today be reeling from the loss of friends and family but as the grieving and burial process came to and end, many were likely to struggle, Christine Macfarlane, Canterbury executive member of the NZ Association of Counsellors said.
"One of the things that happens is that people have flashbacks and intrusive memories that overtake them at any time," she said. "That puts people back in that fight or flight phase and they can freeze - everything just stops."
Macfarlane said those who were in the mosques were never going to forget what happened but the memories should stop being as intrusive and debilitating.
If, after a few weeks, people were still having intrusive flashbacks and were struggling to function, they should seek professional help, she said.
Survivor guilt was another common issue those who were in the mosques would have to deal with.
"Survivor guilt can really erode at people," Macfarlane said. "How come it wasn't me? How come my friend died? How come my father died?
"We are trying to make sense of something that's impossible to make sense of. Some of the feelings you may never be able to understand."
The scenes which faced first responders and medical staff on Friday are ones they will never forget.
St John officer Paul Bennett, who also worked during the Christchurch earthquakes, said the scene on Friday was the "most horrific" he had seen and the recollection of it made him visibly emotional.
"There was a river of blood coming out of the mosque. That's a scene you don't forget. It was literally flowing off terracotta tiles, amongst fatalities."
St John Ambulance staff member Spencer Dennehy said taking one of the first calls was very "distressing" and "emotional, especially given it was in out home town".
The call was from a woman whose husband and 2-year-old were in the mosque at the time of the shooting. Dennehy managed to talk her out of going in after them and was relieved to later find out all three had survived.
"I did think about them all night."
When you're taking calls the main focus is the job, but it was hard to keep from wondering about the safety of your own family and becoming emotional.
Debriefing at the end of the day with her team helped her cope with it. Dennehy admitted she did let herself cry when she got home and struggled to sleep that night but said taking flowers to the memorial "took a bit of the pain away".
Paramedic Karen Jackson said talking with family and colleagues helped her cope as did coming back to work the next day.
"At the time you just click into it and go into a mode and do what you need to do. Other emotions, personal emotions, just get blocked out... and you focus your energy on what you can do. The rest of it comes later on when you've got a bit of quiet time to reflect and deal with in my own way."
A St John spokeswoman said they had an in-house psychologist and support team on hand to work with any staff who needed it.
Association of Salaried Medical Specialists executive director Ian Powell said specialist staff at Christchurch Hospital were coping as well as could be expected under the circumstances.
"Christchurch has experience with the earthquake but this is different with the pre-determination and the whole nature of it being a mass murder," he said.
He said the last few days had been very stressful and as staff had time to reflect on what they had dealt with it was possible some mental health issues could arise.
"I think it's inevitable there will be a lot of emotional stress that will continue for some time. Hospital specialists are human beings but they do see things that others do not."
But, he said the hospital had an employee assistance programme which people could make use of.
Powell said the pressure from here on was likely to fall on GPs and mental health practitioners as people sought help to cope with the psychological aspect of the attack.
Staff and students at schools around the country are today coming to grips with the act of terror which claimed so many lives.
Cashmere High School was one of the Christchurch Schools which felt the full impact of the event.
Two students were killed and another was injured while family members of other students were also killed and injured.
Principal Mark Wilson said the weekend allowed friends and family to come together and start to process things before returning to some semblance of normality today.
"Schools do provide a really important healing place where students can come together, sometimes to get away from their families and to catch up with their mates. Also to be with their teachers who they know and have strong relationships with as well.
Schools also provided some regular routine, he said.
"Research, and also our past experience with earthquakes, shows that type of support for students becomes very valuable in terms of trying to normalise life a little bit more after a traumatic event."
The day started with assemblies to address what had happened.
"We acknowledged the loss of our two students and also the wider loss in our community. It was a great moment for our students and staff to be able to come together collectively before heading away into their normal classes," Wilson said.
Christine Macfarlane, Canterbury executive member of the NZ Association of Counsellors and school issues spokeswoman, said school guidance counsellors and the Ministry of Education's traumatic incident teams would be on hand at schools around Christchurch to talk to those who needed support.
"I think it is definitely a trigger for children and adults to feel this sense of unsafeness and powerless and scared," she said.
"The message is to look after each other - to talk about their feelings, to ensure young children feel safe going about their normal, day-to-day lives. Take the time to mourn and support people who are going through grief."
Where to get help
- 1737, Need to talk? Call or text 1737 to talk to a counsellor (available 24/7)
- Lifeline: 0800 543 354 (available 24/7)
- Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
- Youthline: 0800 376 633, Kidsline: 0800 543 754 (available 24/7)
- Whatsup: 0800 942 8787 (1pm to 11pm)
- Depression helpline: 0800 111 757 (available 24/7)
- Rainbow Youth: (09) 376 4155
- Samaritans 0800 726 666
- If it is an emergency and you feel like you or someone else is at risk, call 111.