Fire crews have extinguished a massive blaze on a chemical truck on Auckland's Southern Motorway that forced evacuations of nearby homes.
Fire and Emergency New Zealand (FENZ) were called to the fire just north of the northbound Papakura offramp before 3am on Wednesday.
A police spokesperson said highly flammable gas canisters onboard the truck exploded all over the northbound lanes and into the bush on the side of the road.
FENZ deployed 12 fire engines to the scene and the blaze has been contained but smoke continued to billow out.
FENZ said there have been a number of evacuations on Harbourside Drive in Karaka where residents are still being advised to keep windows and doors closed and to shelter inside.
Assistant Commander Phil Larcombe said about 30 people were evacuated from their homes and crews are now trying to cool down the remnants of the truck.
"People may still see smoke in the area, but this should dissipate in the next 30 minutes or so," Larcombe said.
"The southbound lanes of the motorway are expected to re-open in the next half an hour. Assessments will continue to be carried out to determine when it is safe to re-open northbound lanes."
The 30 people who were evacuated will be bale to return to their homes soon, FENZ added.
Police said the people evacuated were taken to McDonald's but have just been allowed back into their homes.
Reporter Perry Wilton told AM Early there have been no reports of injuries.
"Great South Road here in Takanini has turned into a highway, all traffic north and south of this incident has been diverted off State Highway 1 and are now on your local roads," Wilton said.
In an update on Wednesday morning, Waka Kotahi New Zealand Transport Agency (NZTA) said the Southern Motorway had fully reopened to traffic.
Resident Anna Shortt told AM she was awoken by the explosion.
"It was a bit unreal. We were asleep and we heard these noises around 3am this morning, we thought it was roadworks, concrete trucks but we went out to have a look and we just saw this massive ball of fire on the motorway," she told AM.
"We just really weren't expecting it at all. It was just crazy, things were exploding and we just didn't know what to expect."
Shortt said there was debris flying everywhere, their front yard was covered in ash and their windows were hot.
"The explosions were insane. Just these massive fireballs and the heat was unreal. By the time the explosions were happening, we were well across the road and inside our neighbour's house and we could feel the force of that," she said.
"But with every explosion there was debris, ash falling everywhere. Our front yard was covered in a really strange blue ash and cars were covered, roofs, everything. There was a huge barrel maybe that exploded and landed just on the other side of our fence."
