The Northern Advocate spoke to the owner of two of the vehicles, who did not want to be named.
She was annoyed her beloved "ancient Mercedes" would be a write-off, but said her Holden ute would "live".
"Which is just as well because anyone who burns a Holden ute is going to hell," she said.
The owner said she was asleep at the time and was woken by the police knocking on her door.
She said the third vehicle belonged to her next door neighbour, and she had heard about a fourth vehicle also set on fire in Whangarei, closer to town.
She didn't believe she had been targetted as the fires were in two different places.
The owner said she had insurance for the vehicles and wanted to "get them fixed, and get on with things".
A Whangarei fire crew attended a vehicle on fire in Rurumoki St, off Hatea Dr about an hour and a quarter later, just after 1am on Saturday.
Police said they believed the fire was also intentionally lit.
Whether the fires were linked would form part of the investigation, Gray said.
Police said there have been no arrests so far and investigation into the arson is continuing.
Police were asking for anyone who knew anything about the incident to contact the Whangarei Police Station.