A person has died at the scene of a stabbing in Whanganui.

Five other people were taken to hospital with moderate to serious injuries after the incident outside the New World on Wicksteed Street.

Police say a person is in custody and a homicide investigation is under way.

Emergency services were called to the incident around 4:20pm this afternoon. 

A worker from Te Oranganui, who did not want to be named, said a colleague witnessed the stabbings.

Te Oranganui nurses and a doctor ran to the aid of the victims.

"When I got there, there was one lying on the ground. It was a big girl. She'd been stabbed, it was bad."

Blood spilled in the New World carpark in Whanganui. Photo / Lewis Gardner

The worker said two other people who had been stabbed were walking around.

"You could see it. He was holding his neck and blood was pouring out. On his back, you could see where he'd been cut.

"There was another lying down, she wasn't moving. She was an older lady."

The worker believed the stabbing victims were four members of one family.

Part of the New World carpark in Whanganui remained cordoned off after multiple people were stabbed. Photo / Zaryd Wilson