A police raid two years ago on a Sydney gallery exhibiting pictures of semi-naked girls by celebrated Australian photographer Bill Henson provoked an anguished debate about art versus pornography.

Now Henson has spoken publicly for the first time - and his comments are likely to reignite the controversy.

Addressing a 1000-strong audience at the Melbourne Art Foundation, Henson dismissed the criticism that his young subjects were unable to consent to modelling nude.

He also claimed that posing for his photographs was less harmful than engaging in contact sports.

Henson has been producing moody images of children for decades but he came to the attention of mainstream Australia in 2008, when police swooped on the gallery - hours before an exhibition was due to open - and seized 20 images of a 13-year-old girl.

The photographs were denounced by then Prime Minister Kevin Rudd - who had not seen them - as "absolutely revolting". Police vowed to lay pornography charges but quietly abandoned their investigation a couple of weeks later, having found no evidence to justify a prosecution.

While leading figures in the art world defended Henson's right to create challenging works, the photographer himself has laid low since then.

He refrained from speaking out during another media storm, triggered by publication of a book about the affair, which revealed that Henson had scouted for models in a primary school playground.

In his Melbourne speech, he disputed the idea that his child models had been exploited. "Kids do consent to all kinds of significant things all the time. A 10-year-old can consent to something that might otherwise be unlawful assault: dental work. In this state, a 15-year-old can consent to a sex change. Children's consent plays a major part in divorce proceedings."

Henson - whose photographs are in Australia's major public collections, as well as New York's Guggenheim Museum - said there was no evidence that life modelling caused physical or psychological harm to children. By contrast, he said, a 12-year-old boy playing football could "find himself in a wheelchair" for the rest of his life.