Hans Compter came across a hidden gem when he entered a hanger at a United States airfield, near the Mexican border, in 2007.

A rare 1929 Packard Type 640 Custom Eight had been gathering dust for more than two decades.

Compter, 71, bought the car from the former San Diego county supervisor it belonged to and shipped it back to New Zealand, where he runs a vintage vehicle restoration business in Whangarei.

After $150,000 of work that took place over the past 20 months, the now restored Packard was in Auckland yesterday being prepared for shipment this week to its new owner in Belgium.

Compter said his company, Comps Impex NZ, conducted a "ground up" restoration.

This included replacing parts of its partially wooden frame, as well as its dashboard and upholstery.

Much of the work was carried out by Compter's son Dennis, who said one of the most challenging parts of the job was rebuilding the car's Bijur automatic lubrication system which is operated by a handle beneath the steering wheel and lubricates the chassis.

"A car owner back then would have been a gentleman and to get down and grease the thing was not considered the done thing," said Dennis.

Compter did not want to say how much the Belgian owner had paid for it but the car was now worth between $400,000 and $500,000, he said.

Compter said the vehicle, powered by a 6.7 litre "Straight Eight" engine, could reach 100km/h and easily cruised at 80 to 90km/h.

The new owner was planning to take it on club rallies, he said.

Comps Impex NZ, which Compter said had an annual turnover of between $500,000 and $1 million, was working on several restoration jobs for customers around the world.

The company also had a private collection of 130 cars including an Italian Lancia once owned by former Argentine First Lady Eva Peron.