The last time the photographer was in harbour city in 2010, more than 5000 people disrobed in front of the Opera House as part of Mardi Gras.

It’s always a challenge to find enough people willing to take their clothes off in public, he told AAP, but those that do like the result.

“They really enjoy looking at an image that they participated in, and they know the artist is trying really damn hard to create a strong work,” he said.

The shoot will be held on Saturday November 26 at a yet-to-be-revealed beach location as part of National Skin Cancer Action Week.

There are hopes 2500 people will participate, commemorating the more than 2000 Australians who die from skin cancer each year.

Australia has one of the highest rates of skin cancer in the world, with two in three people diagnosed by the age of 70.

Tunick himself plans to get a skin check in Sydney, and speaking via video call from New York, he shows off worrying spots on his arms and hands.

He says it’s been ten years since he last had a check.

“I might be coming to Australia for bad news – hopefully not,” he said.

Growing up in the 1980s, Tunick worked as a lifeguard in New York state’s Catskill Mountains, and his efforts at skin protection were limited to wearing a baseball cap.

Despite summers spent supervising people wearing very little, the crowd-management skills so essential to his artworks come from elsewhere.

From the age of 13 Tunick went to New York Military Academy, where he worked his way up to the rank of captain.

“I would march people left and right, over hills, through rainstorms, so that’s how I started working with groups,” he said.

He’s now been photographing naked bodies in public places around the world for almost three decades, including some 18,000 people in Mexico City’s central square, crowds on the desert sand in Nevada, and even brave souls on a glacier in Switzerland.

After all this time the nude en masse still fascinates him.

Bodies can appear powerful, Tunick believes, enlivening spaces and pushing cultural issues, but they can also show the fragility of human life.

“Sometimes the body is very vulnerable en masse and you see how sensitive the human sculpture can be,” he said.

The Sydney event is being run in collaboration with charity Skin Check Champions, which runs free clinics in high-risk communities.

Tunick said the organisation may not have the crowd-pulling power of the Mardi Gras, but in the end, size doesn’t matter so much.

“You know what, I think it’s more about the act of showing up and participating,” he said.

People can register for the event here, with parental permission required for those under 18.