Reports of large explosion in South Auckland

One person has died in an explosion at a hazardous materials recycling business in South Auckland.

Emergency services rushed to the industrial site on Bolderwood Pl, Wiri about 1.35pm.

A St John spokesman said one person died at the scene. Four others received minor injuries and another person was being assessed nearby for asthma-related symptoms.

The Fire Service said in a tweet that the explosion was "huge".

The incident was caused by welding.

The explosion was at Salters Cartage, a spokesman for the business said. Salters Cartage is a hazardous materials recycling business.

The force of the explosion blew photos off walls a block away, shook buildings and was described as sounding "like a bomb".

Specialist fire investigators are at the scene, as well as dozens of emergency crews.

Three fire trucks can be seen and several police cars and officers are manning the road.

Where it happened:

Roscommon Rd - which Bolderwood Pl runs off - has been reopened, but motorists are being asked to avoid the area. Langley Rd, Mayo Rd and Bolderwood Pl remain closed to traffic.

A worker at a nearby business told the New Zealand Herald a loud noise "like a bomb" was heard.

"It was a large bang nose and then the cops and ambulance and fire all came.

"It sounded like a bomb - it was a big noise."

Transdiesel service adviser Peter Swann said he was on the same road as the accident.

He said the road was blocked and police, firefighters and ambulances are everywhere.

"Our building shook like crazy, we thought it was a plane gone down."

A man who works just around the corner said the explosion shook his office.

"And massive pieces of debris were visible in the air immediately afterwards. There was a strong smell of gas in the area as well," he said.

Carol Lucioni, a shop assistant at Guthrie Bowron Manukau, said shae and a co-worker heard a loud bang and their two-storey building on Ronwood Ave shook.

The Guthrie Bowron building is about 5km from the explosion site on Bolderwood Pl.

"We were in the back room and we heard the bang and shook, and we thought it was somebody upstairs."

Ngaire Gedye, who lives in Hill Park, said she was on the phone when it happened.

"My whole house just shook, I could see all the neighbours rushing out to have a look around."

She couldn't see anything from where she was.

"But given the distance it's amazing how strong it felt," she said. "I could feel my house shaking, thought it didn't last for very long. It was over before it started."

On a Manukau community Facebook group people reported hearing a "big bang".

One woman said sirens were "going crazy" in the area and another can see smoke billowing into the sky from her home.

"Massive shake and boom in Hillpark... Heaps of sirens now," said Clare Scott.

Kate Dillon said her house went crazy.

"I thought my roof was caving in...I went outside and everybody was looking for the cause of it...Craaazy!"

Vince Barrett, who lives in Papatoetoe, said he felt the explosion.

"Our house which is on piles shook."

He was on the computer at the time the explosion went off and remembers hearing a muffled bang.

Mr Barrett said since he was about 7-8km away from the site, he didn't see anything.

- NZME.