"Disposing of an unwanted car can be difficult and expensive," Stock said.
"If it's not mobile or roadworthy, the cost of transport would often be more than the value of the vehicle, if the vehicle had any value."
She said there are some car disposal companies that would collect old cars, but this isn't a well-known fact.
"So dumping can appear to some to be an easier option," Stock said.
Glenfield resident Pauline Soo said a damaged car left opposite her house on Shanaway Rise was an "eyesore" to the neighbourhood.
"It's been there since June, with flat tyres, damaged car body and cracked windows ... clearly not driveable," Soo said.
"Neighbours have called Auckland Council multiple times, but we've been told it can't be towed away because it's got current registration."
Jon Uele, of Otara, said his friend dumped a car when he found out the cost to replace his radiator was more than what the car was worth.
"Makes more sense to just abandon it," Uele said.
"And with petrol prices these days, it's cheaper to take the bus."
But Stock said dumping was irresponsible and should never be an option for those wishing to dispose of their cars.
"They should sell it, if it still has a value, or give it to another family member who could use it or sell it to a wrecker," Stock added.
She said fuel price changes did not significantly impact the overall costs of running a car, and the operating costs played the biggest part in what people decided to do with their cars.
AT spokesman Mark Hannan said the number of abandoned vehicles was growing.
He said the process of managing abandoned vehicles took time because of legal requirements that included having to notify the last registered owner.
"This includes a letter to the person's last known address and in national papers," Hannan said.
Vehicles would be removed from the streets only if they were in a poor state or deemed to be a risk to the public, such as those with broken windows.
Hannan said towed vehicles go to storage at the cost of the ratepayer of about $20 per day per vehicle.
"Then there is a process where we have to try to track down the owner before they can eventually be sold, all at a cost of the ratepayer," Hannan added.
Meanwhile there is a petition seeking Parliament to undertake an inquiry into ways in which fuel prices could be lowered.
The petition, which so far has 2132 signatures, said petrol prices needed to decrease "so people can afford fuel to get to work so they can support their families".