The woman picked the car up and drove it back to her Auckland home before changing its ownership to her own name and selling it on for $1000 at a dealership in Western Springs, he said.
Police said the woman admitted she didn't have permission from Rae Portman or her family to collect the vehicle in an interview on September 5.
She appeared in the Auckland District Court this morning and has been remanded until November 20.
Prosecutors are seeking $2000 reparation to be paid to Ms Portman's mother Rebecca Norton.
Ms Norton has revealed her daughter was four months pregnant when she disappeared.
She has issued a public plea for anyone who has information about the whereabouts of her child and unborn grandchild to come forward to police.
CAN YOU HELP?
Contact police on 0800 723 767, Crimestoppers anonymously on 0800 555 111 or visit the Where is Rae (Bok) Portman Facebook page.