Crowds are sent running as a fireworks display in Christchurch turns bad.

This story contains graphic images.

A 4-year-old boy may need a skin graft after being burnt by fireworks at a church-run event in central Christchurch.

Mason Timaloa was one of six people taken to hospital after fireworks "exploded" into the crowd at a display organised by City Church Christchurch on Manchester St.

SUPPLIED Mason Timaloa, 4, suffered burns to his chest and stomach when he was hit by fireworks at a public display in Christchurch on Friday night.

The fireworks display started just before 9pm on Friday and quickly went wrong as fireworks somehow shot into the large crowd.

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A St John spokeswoman said six people were taken to Christchurch Hospital with minor and moderate injuries.

SUPPLIED Leon Timaloa says his son, Mason, is doing well despite his injuries.

Leon Timaloa's son, Mason, was sitting behind a barrier with a friend when he was suddenly hit by one of the fireworks.

"All of a sudden we saw [fireworks] shooting everywhere. He was screaming. I saw that he had embers on his top . . . I picked him up and put him over my shoulder and ran to the first aid station."

The fireworks had burned a "great big gaping" hole through the three layers of clothes Mason was wearing and into the skin on his chest and stomach.

SUPPLIED Dad Leon Timaloa says Mason may need end up needing a skin graft.

First responders ran water over Mason's burns, then wrapped them in clingfilm before he was taken to hospital.

"He was good and calm throughout," his dad said.

Mason stayed in hospital overnight and had surgery on Saturday morning to remove the burnt skin from his body.

"We maybe have to look at a skin graft down the track."

Despite Mason's ordeal, Leon Timaloa said he thought the fireworks event had been "well organised" and he had "no ill-will against the organisers".

Coordinators had been going through the crowd before the display started, making sure people were standing behind the barriers and that everything was set up properly, he said.

SUPPLIED Mason's family hope to take him home from hospital soon.

"One of the things that could come from this is to move the distance people view fireworks from.

"It's probably a good wake-up call for anyone else organising these events, whether it's organising your own or a public display."

Amy Swain was at the event with her husband and two young children and said it was "just luck" that they were not hit by any fireworks.

SUPPLIED People were sent running as the fireworks rained down on them.

The family were sitting a few rows back from the barrier and she had a "weird feeling" about the set up.

"It looked really unsafe. It looked like they [the fireworks] were on gravel. I think one stayed up but the others fell over and started shooting at us."

Swain quickly shielded her 3-year-old daughter, while her husband – whose arm was singed by one of the stray fireworks – protected their other daughter.

"My 6-year-old was screaming. She was so terrified. We were out of there, we didn't wait to see what happened."

Swain said everyone was "just running" to escape the fireworks through the only exit out of the venue.

"It was a scramble . . . it was just fend for yourself."

The experience had not put her off all fireworks, but had made her more wary.

"[The organisers] definitely had the best intentions to make it a good family night out but I think there was a lot of safety precautions lacking."

A post on the church's Facebook page on Friday night said "something went wrong with the fireworks".

"In the interest of public safety the event was immediately stopped and we are investigating what went wrong," it said.

"We apologies to everyone, especially those who were hurt."

The event was billed as a "fun family night out", with games, bouncy castles, face painting and a "spectacular" fireworks display.

Hundreds of people were expected to attend the annual "kid friendly, non-alcoholic" event.

A WorkSafe New Zealand spokeswoman said the agency had been notified of the incident and was "making initial inquiries".