Armed police are raiding a car yard in West Auckland, seizing a motorcycle and inspecting other vehicles at the site.

Officers were armed with pistols and Tasers as they swarmed a warehouse in Bentinck St, New Lynn. A witness says they had been there since about 8am.

"There's about 16 armed police officers - they've got pistols on them. They're pulling out classic vehicles from a car yard there and blocking off the road."

So far a late-model motorcycle has been seized and put on a transportation truck.

Officers are also inspecting a luxury Mercedes SUV and a GLA250 hatchback.

Police are inspecting this luxury Mercedes SUV.

A witness said he had seen armed police stationed outside a panelbeaters establishment further down the road.

Another witness who works on Bentinck St said dozens of police officers were taking vehicles out of a large, unnamed warehouse.

He said he arrived for work nearby at 6.30am, police arriving shortly afterward at 7am.

"There was a big raid about 7am, the coppers came in. They took the dogs inside," the man said.

"There's a lot of cars being moved and people going from here to there."

Meanwhile, another worker on Bentinck St said a police dog unit had been sweeping the area, along with officers with mirrors checking under cars.

A police spokesman confirmed police were there in relation to an ongoing operation.

"Police are currently carrying a number of pre-planned search warrants this morning, as part of an operation,'' he said.

The spokesman said police were not in a position to comment further about the situation at this stage.

"We expect to provide media with an update later today,'' he said.

On Sunday, four performance vehicles worth over a collective $300,000 were stolen from J's Auto Import which is located a short distance away on Great North Rd.

In scenes reminiscent of Hollywood movie Gone in 60 Seconds, thieves smashed their way into the car dealership and stole the vehicles and a safe.

A 2015 Porsche GT3 worth $220,000, a 1999 Mitsubishi Lancer Evolution V and 2007 Honda Civic Type-R, both worth $20,000, were taken.

However, police said the operation today was not in relation to the stolen vehicles over the weekend.

The owner, Leo Jiang, said his prized track car was also stolen. However, it was found later that day about 10 minutes away from his warehouse.

"The total worth is more than $300k added up - it's not right," he said.

"They took my safe as well and it's bolted to the ground. I don't know how they did it, they just took the whole thing. It's not that big but quite heavy."

The safe contained $6000 in cash and his passport, he said.

As of midday Wednesday, Jiang said his Porsche, Honda, Mitsubishi, and safe had not yet been located.