Bodies lay across the footpath and a father who had been shot cared for his critically-injured 5-year-old girl just outside the scene of a mass mosque shooting in Christchurch.

At about 1.40pm a gunman entered a mosque on Deans Ave near Hagley Park packed with 300 to 400 people for Friday afternoon prayer, and opened fire.

Another shooting took place at a Linwood mosque, with reports of between nine and 27 people killed in both attacks.

South Island manager for Naki Labour Hire Carl Pomare and one of his workers were driving along Deans Ave when they started seeing people running towards them.

"We were just opposite the mosque and we saw a whole of lot people pouring, out running like their lives depended on it. I said to my mate, 'S***, what do you think is happening here?'

"Then we heard the bang, bang, bang, bang, bang.

"We heard rapid fire semi-automatic shots, and saw people running out of the mosque, fall on the ground in front of us on the side of the road," Pomare said.

"We saw them being shot. Being mowed down as they were running away.

"I said to my mate, 'We need to do something'."

There were no police nor ambulances on the scene at that stage, and just another company truck that had stopped to help out.

The victims included children.

"One girl looked about 5 years old, she was critical, and her father had also been shot. He was nursing her. We just thinking, 'Come on ambulance, come on'."

Pomare and others on the scene decided they could not wait, and put her into the back of a 4WD with her father and whisked her off to hospital.

"I just hope she survived. She was not in a good way.

"My worker was nursing a guy who had been shot in the back three times for about half an hour, saying, 'Hang in there buddy'. He passed away in my his arms."

Carl said it was "absolute carnage" with shots still being heard in the mosque.

"People who had escaped said a gunman had just come in and started rapid firing in the middle of the mosque, with a helmet on.

"There was not much yelling, nor sirens though. Another company stopped in front of us and got out too, they were great, putting their lives at risk. There was still shooting in the mosque while we were trying to help people."

The workers were in the cordon for about an hour and a half doing all they could to help- the injured.

"I said to my worker, this does not feel like Christchurch in New Zealand.

"We've just seen people in front of us being shot, mowed down by a semi-automatic rifle, just ordinary people. It is pretty surreal."

Pomare said now it was starting to sink in.

"I just can't believe it has happened. We put ourselves at risk, but in the spur of the moment you don't think of your own safety, just these bodies that were lying there, just ordinary people."