Mr Thwaites said told the Bay of Plenty Times from Bernard St that the mini was his and he was so happy to have it back.
Police were responding to the find and are expected to tow it away for investigation to help track down the thief.
Mr Thwaites had used the car as a runabout and was hoping to one day pass it on to one of his grandchildren.
"It's just my handy little wagon to get around in and everybody sort of knows me from it. It's a little car I was going to do up and hand down," he said.
Friend Steven Miles posted on the Facebook page, Papamoa, New Zealand asking people for any information on the Mini's location and to keep an eye out.
So far, the public appeal for help has been shared on social media over 800 times.