A person has been shot dead after fleeing officers at the country's largest shopping mall in an incident that sparked a major response from emergency services, workers locking themselves and others inside their stores and the shopping complex being put into lockdown.

For those inside Sylvia Park, uncertainty turned to terror and fear as workers reported screaming and Police with guns who were moving customers and telling them to lock their doors.

Dozens of Police cars would swoop on the shopping complex in Auckland's Mt Wellington and patrol cars with their lights still flashing remained scattered across the sprawling car park more than two hours later.

Nandan, a manager at the mall's Timberland store, was locked inside his back storeroom after quickly realising that what he thought was people having fun was anything but.

"Like I was sitting there in my back room, like having my lunch and waiting for my next meeting, and suddenly I've heard a few people screaming," he told RNZ's Checkpoint.

"And I've heard a weird sound, and I just about came out and two of my staff came running inside the back room and saying 'did you hear it? It's people are shooting, like there's a shooting," he said.

"And as soon as I went close to the main door, the main gate, I've seen a policeman there and other people are running in front of the Timberland and JD [store]".

"And then suddenly police, uh, uh, ask us, and uh, one of my colleagues, to lock the door," Nandan, the store manager said.

"And since then, we are sitting here, uh, back in the back room, uh, not going on the floor, and waiting for next instruction from Police."

Nandan said he heard two people screaming but thought it was people having fun.

"But then one of my colleagues came in and said it's not normal."

Others also reported what sounded like gunshots.

One retail worker said armed police locked down half the mall and turned people away.

He said he was concerned for his staff's safety and that people in stores nearby were feeling anxious. "I'm not going to lie ... some of them are very antsy."

Another worker said he was in a storeroom when he heard yelling over the radio.

Other employees told him they had seen a man running and heard multiple shots - between four and five but could not agree.

"It's really horrible," he said

He said he saw helicopters, fire trucks, police cars and officers with black vests through the store window, and staff locked their doors and stayed inside.

Hato Hone St John said it was alerted shortly before 3pm and sent an ambulance and other vehicles.

Later, Police were seen outside the Footlocker store putting up a white sheet.

Police vans began arriving to help carry out investigations.

Police initially released few details, but said there was no risk to the public.

Just before 6pm, Police said an armed man fleeing them had been shot.

"Earlier this afternoon, at around 2pm, Police received information about a theft of an air rifle at Gun City in Penrose," Supt Sunny Patel, the Auckland City District Commander said.

"The offender has fled in a vehicle and units have been dispatched. The Police Eagle helicopter deployed to the area and has located the white Suzuki Swift travelling near Sylvia Park."

Patel said the vehicle was tracked going into Pakuranga and they then saw it being driven erratically towards Panmure.

"Units successfully deployed spikes as the vehicle continued towards Panmure. The vehicle continued towards the Mount Wellington Highway, still being driven in an erratic manner."

It was outside Sylvia Park the vehicle got stuck, Patel said.

"At this point, approximately 2.50pm, the offender fled on foot carrying a long-barrelled air rifle. He has run on foot onto the grounds of the shopping centre.

"Units have pursued the offender as he headed towards an entrance into the shopping centre. Whilst still in possession of the air-rifle, he has been confronted underneath an overpass where he was been shot by Police."

Police said first aid was given straight away but the offender died at the scene.

"Police have now stood up a critical incident investigation into the events that have unfolded this afternoon. Our investigation is still in the very early stages of piecing together all the events."

Speaking to media at around 7pm Supt Sunny Patel said the man was known to police but not wanted.

Patel confirmed the man was under bail conditions but had not breached those conditions.

He would not go into details about the identity of the deceased man, saying the next of kin had not yet been notified and police were planning to do so on Thursday night.

He encouraged anyone with information or footage to come forward and said the ongoing investigation will look into details including how the rifle was stolen, whether it was loaded and what the potential intentions of the man were.

One witness told Stuff they saw armed police chasing after a person before shooting him down outside Footlocker.

"They follow the guy and then they shoot him. Three shots, he was dead."

The witness said they had initially seen the man that would be shot, run past them.

"He was just running... I couldn't tell what his intentions are, I'm sure they weren't great."

The witness told Stuff they could tell something was wrong.

"There was a pistol in his hand but I kind of didn't find that out until later.

"Knowing that he was so close to me with a gun even is just kind of scary, but he looked like a normal dude."

As darkness fell, cars that were initially stuck behind expansive cordon tape began being allowed out while inside the large mall, shopping continued.

A large barricade was put up inside blocking shoppers from the area of interest on what would normally be a late night of shopping on a Thursday.

See how the incident unfolded below...