He woke to 20-40 gunshots. Moments later a man fleeing for his life burst through the door

A Christchurch resident revealed he was sleeping when he woke up to 20-40 gunshots and a man fleeing into his house with a bullet wound 7cm into his leg after a mosque shooting.

A young man and his three flatmates, who live on Brockworth Place near Masjid Al Noor, rushed to the aid of a male Muslim who fled to his house after the mass shooting.

"I had to deal with that really quickly considering I just woke up," he said.

"We called an ambulance and police and I applied pressure to the wound."

"It's just human nature to help someone in that situation."

When the Muslim man ran into their house he told the young man that he had just been at the mosque, multiple shots were fired and he fled the scene immediately looking for help.

"[The victim said] he didn't see the armed gunman but he heard bullets ringing around, one had just missed his stomach area. He would have had a far more serious injury in that case." he said.

"I thought he was making it up ... I didn't realise something of this magnitude could happen in New Zealand.

"I was just in an utter panic."

He believed the bullet was a .223 calibre from a high powered rifle as the bullet was 7cm into the man's leg.

"Based on hearing it, it was very high-powered. [I] could hear the gun barrel going from 5km away."

An ambulance never arrived at this house, so a flatmate drove the victim to the hospital.

He first thought the gunshot was from the armed offenders' squad, but said when the victim ran in it shattered his thought.

"I send my condolences to the families and people involved also," he said.