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St John Ambulance staff who responded to the terrorist attack on Friday have spoken of the horrific conditions they saw, and the pride they feel from being part of an efficient response that is believed to have saved lives.

"There was a lot of blood, a river of blood coming out of the mosque," said ambulance officer Paul Bennett, who was at the Deans Ave mosque.

"That's a scene you don't forget. It was literally flowing off terracotta tiles, amongst fatalities."

He became emotional and fought back tears as he recalled the "most horrific" scenes he had ever witnessed.

He didn't go into the mosque on Deans Ave, but approached the entrance under the protection of armed police.

"We tried to get our stretcher into the mosque but we couldn't because there were fatalities in the way. We ended up having to lift the bodies over the top of other bodies on to stretchers."

Flowers and messages of support and love for New Zealand's Muslim community at a police cordon outside the mosque on Deans Ave, Christchurch. Photo / Michael Craig

He said he had to lift injured bodies over dead ones to "do his job".

"Speed was of the essence. The journey from the mosque to the ambulance to the emergency department, we knew was critical. The injuries were all critical."

Bennett was likely one of the senior officers sent into the mosque by Jason Watson, an ICU paramedic who was organising logistics on the ground in front of the mosque on Deans Ave.

Other officers were stationed by the entrance to be handed patients to take to hospital.

"Initially there was chaos. That's the nature of it," Watson said.

He said that police provided a shield of cover. At one point, police told Watson to get on the ground amid fears the gunman might be returning, but that threat was soon cleared.

"A good half of the patients going into the back of ambulances I expected to die within an hour," Watson said. The fact that only one had was an "incredible" testament to the work done by the ambulance officers.

"What is really incredible is the fact that our team went and did this job and then turned up to work the very next day ... that says a lot about the dedication of the people in this community to look after our people."

Spencer Dennehy , 24, had only been in the job answering emergency 111 calls for nine months when she took a "very, very distressing call".

"It was very emotional, given it was our home town. I didn't realise how serious it was ... It was very, very distressing, and having to be strong for the caller, but it's very emotional at the same time."

A lady crying for her husband and 2-year-old baby was on the call, which Dennehy described as hysterical, and she told her to stay away from the mosque on Linwood Ave.

The 2-year-old could have been one of the bodies that were handed to paramedic Karen Jackson as she arrived at the mosque on Linwood Ave with armed police.

She said it was an intense situation as the shooter was still at large.

"Bodies on the floor. The walking wounded were not there, so everyone was either already deceased or very critical ... [We were] having to step over bodies and find a position between the blood and bodies to treat the patients."

The injuries she saw were mostly gunshot wounds, entry and exit wounds, internal and external bleeding, and "people deteriorating in front of us".

"The mood was just to get on with the job ... The priority was on treating the ones we were mostly likely to help and get to hospital."

Dawn Lucas, an emergency medical dispatcher who directed crews to the jobs that came via 111 calls, said the event made her focus.

"Once you realise the enormity of it, it's just making sure the crews are safe, making sure you're sending everyone to the right place."

She said sending colleagues to potential danger made her feel "really sick", but that was allayed by the professionalism of the people.

"My focus initially was on the Deans Ave mosque. When we realised that the Linwood [mosque] was similar, it was a matter of getting enough resources to both, and making sure we didn't overextend."

She said the operation felt like it "went by really quickly ... it started with a bang, and then it just stopped. Very quick. Adrenaline ... it was a very surreal event afterwards when you have time to actually reflect."

All staff speaking to media talked about the need to process the traumatic events of Friday.

Dennehy said she she had a cry that evening at home. She also laid flowers at the memorial, which "took a bit of the pain away".

"At the end of the day, we are human. It is very emotional for us as well."

Territory Manager Craig Downing acknowledged all those who lost loves ones, and pride for the work of the ambulance staff.

"We call it a family because we are a family."

Downing said the arrival at the hospital ED was so well set up that it was quick to drop off patients and then speed off back to the mosque.

He said those who worked behind the scenes did just as much good work as those on the front lines.

St John Canterbury District operations manager Wally Mitchell, who was only three weeks into the job, praised the staff and said the ambulance processes came together in a seamless way.

"It was a response I feel very privileged to be a part of … It was an amazing team.

"They saved lives on the day."

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