Expo co-ordinator South Murdoch said the event was the first of its kind in Dunedin.
Displays would reflect the evolution of tattoo design and the increasingly diverse people who were getting them.
"Tattoos are far more acceptable, but people like businessmen often hide them," Ms Murdoch said.
That was because in the past tattoos had been associated with criminals.
Now people chose a tattoo because it said "something about the individual, like jewellery or clothing".
Visual Intelligence manager Macaela Manuel said her husband Aaron, the sole tattooist at their Dunedin studio, did between three and five tattoos a day, "six days a week" to meet growing demand.
Mrs Manuel agreed that as it became more socially acceptable, people acquired tattoos as another form of personal adornment.
Yesterday morning, a man booked an appointment for his first tattoo - a 70th birthday present to himself, she said.
"Many older people tell us they always wanted one, but there was a stigma attached."
Mr Manuel will spend two days tattooing a large dragon design on a man's back at the expo, which is being staged at Sammy's.
Chris Downing, of Dunedin, became a tattoo artist 12 years ago after working as an oil rig engineer.
He was selective about his clientele, and refused to do work which "people might regret later in life".
Mr Downing completed up to 1000 tattoos every three months.
"All types of people are getting tattoos . . . The last full back I did was on a doctor," he said.
Dunedin psychiatrist Chris Wisely also said tattoos were an expression of individuality.
"They are ornamental, but also have shock value if they are used for social identification, saying things like: 'I've been in jail'.
"There's the religious and cultural reasons, but also those who take pleasure from the release of endogenous opiates during the tattooing," Dr Wisely said.
The Dunedin Tattoo Nations Expo will take place at Sammys Dunedin throughout the weekend.
