Cat Hunter came across the painting in an op shop in Perth four or five years ago, where it was for sale for $10.
"I thought 'Well, the least I can do is buy that and then wait till he dies and then sell it to some sad Tom Jones fan'," Ms Hunter said.
When she returned to New Zealand with her partner the painting came too and it now hangs, in its tatty frame, on a wall near her front door.
Visitors often remark that the eyes appear to follow people, like those of the Laughing Cavalier.
"Tom follows you everywhere . . .
"There's something about Tom, and now I'm sort of starting to think I'll never sell him."
Ms Hunter says the painting is in the style of an old master, is dated 1969 and is signed by VA Kirton, of Skegness, Lincolnshire.
Although "not the biggest Tom Jones fan in the world", Ms Hunter had hoped Sir Tom's signature would add value to the painting, and she thought Sir Tom might like to see it anyway.
However, a spokeswoman for tour promoter the Frontier Touring Company, told the Otago Daily Times Sir Tom (70) was "not doing" events like signing 41-year-old oil paintings of himself.
Ms Hunter, who has an 8-week-old baby and another preschooler, turned down her mother's offer of tickets to tonight's show.
"I admire him greatly because he's managed to hang around for so long . . .
"If I did go to the concert I think I'd quite enjoy it, but because of circumstances I'm not breaking my neck to go there."
