Flight KA691 which was due to fly to Penang in Malaysia, collided with the maintenance van while taxiing on the tarmac.
"While the aircraft was taxiing away from the departure bay, one of the engines was hit by a maintenance vehicle operated by another company," a Dragonair spokesperson told CNN.
"The aircraft is now being inspected by our engineers and our maintenance service provider," the spokesperson said.
Dramatic footage shows the A330 passenger plane's engine crushing the van's roof, just inches from the driver's head. He was later taken to hospital, a Hong Kong International Airport spokesman said.
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But reports said the driver of the van suffered head and shoulder injuries.
He was conscious when rescued from the vehicle and taken to North Lantau Hospital, South China Morning Post quoted police as saying.
Five fire engines and two ambulances were called to the scene.
"Our plane was about to go into the runway when the van hit the engine and got stuck inside," said witness Toshiro Kobayashi, who filmed dozens of emergency staff attending the scene.
Passengers were asked to disembark and the flight finally departed at 7.44pm local time according to Hong Kong International Airport's website.