By Mike Collett-White and Soheil Afdjei

LONDON, Sept 8 (Reuters) - British artist Damien Hirst says his decision to hold an open auction of new works rather than go down the more traditional route of galleries and dealers is his way of being a modern-day punk.

The 43-year-old shocked the contemporary art world when he announced that more than 220 new works, collectively called "Beautiful Inside My Head Forever", would be auctioned by Sotheby's in the first sale of its kind by a major artist.

One of the world's most bankable painters and sculptors, Hirst's works are expected to raise over 65 million pounds ($116 million), adding to his already sizeable fortune that one newspaper said already amounts to more than $1 billion.

Speaking to Reuters at a press preview of the works in London, Hirst was unapologetic for mixing creativity with cash despite accusations he is producing only for profit. One commentator referred to the auction as a "clearance" sale.

"I think the world is changing, you know, I mean I was approached by the auction house, when it wasn't my idea," said Hirst, surrounded by works that include his trademark animals in formaldehyde, spin and butterfly paintings and variations on the pill cabinets.

"The commercial aspects of art and all the money side of things makes the art feel very much alive for me, so (it) just makes sense to go in there," he added.

"I like risk and craziness and people saying 'Oh my God', and I think that you get a lot of that, you know. I'm a punk at heart. I was too young to be a punk, I think I was 12 in '77, so I think I've waited until now really to do all that stuff."

MONEY GENERATES INTEREST

If the sale does raise tens of millions of pounds, at a time when the art market is booming despite economic gloom elsewhere, it could help attract more people to art, he argued.

"I mean, what's great about the money is that if it does raise a lot of money, then a lot of people who aren't interested in art ... sit up and notice, which can only be a good thing."

In a separate briefing with journalists, he pointed out that galleries take up to 50 percent of the proceeds from an artist, an "extortionate" amount.

But he was quick to stress that he did not want to burn bridges with galleries, which have helped turn him into arguably the world's most influential living artist, saying he would exhibit with them again in future "if they'll have me".

Hirst has come under fire from some top critics, including Australia's Robert Hughes, who has called his art "tacky" and "absurd".

Hirst brushed aside the comments, adding: "He's a very intelligent guy, and you really admire a lot of the books that he writes, but, unfortunately ... he's just not very up-to-date."

Estimates at the sale, to be held over two days on Sept. 15 and 16, range from 15-20,000 pounds to eight to 12 million pounds for "The Golden Calf", a bull in a tank of formaldehyde with its head crowned by a solid gold disc and its hooves and horns cast in 18-carat gold.

The sale coincides with the 20th anniversary of the Freeze exhibition in London which launched the careers of Hirst and some of his fellow "Young British Artists".

(To read more about our entertainment news, visit our blog "Fan Fare" online at http://blogs.reuters.com/fanfare)