The teen then locked the doors, climbed into the driver's seat and drove away.
Police stopped the man on the Taihape-Napier Rd at the Springvale Suspension Bridge, 40km northeast of Taihape, and arrested him again.
He was placed in the second police patrol vehicle in handcuffs, but while the officer was transferring equipment from the back seat into the boot, the man again climbed into the driver's seat and stole the car.
According to police, both vehicles could be driven without keys, as they have keyless entry and start technology, and both were running while the officers held the keys outside.
Police said the second vehicle was running because the officer needed the light bar, as the car was in a secluded rural area and the officer had to pick up road spikes and process the arrest.
The officer called for assistance and the stolen vehicle was spiked at Te Moehau Junction soon after.
The man fled on foot before being found and arrested a short time later.
"These events should not have happened," a police spokesperson said.
"The work police do is unpredictable, as are the people we deal with. Events move fast, and situations can be dynamic and difficult.
"These incidents are concerning, and lessons will be learned from them."