Sculptor Antony Gormley is launching his latest work - Six life-size figures along the Water of Leith

Gormley, whose sculptures of human figures are all based on casts of his own body, will be in Edinburgh next week to celebrate the launch of 6 Times, his first public commission in Scotland. Six life-size cast-iron figures are currently being hoisted into place in a series of locations along the Water of Leith between the Scottish National Gallery of Modern Art and the sea.

The 400,000 project marks the culmination of more than three years of intricate planning, negotiating and fund-raising.

"It's very exciting that it's now going public," says senior curator Philip Long from the SNGMA, who has been working on the project since its inception.

"I was standing on the bridge in Stockbridge when one of the figures was lifted into place and people were applauding. It's an amazing experience to be part of, and I hope it will be something people in the city are proud of."

If past experience is anything to go by, people certainly take Gormley sculptures to their hearts. More than 150,000 visit the Angel of the North in Gateshead every year, and Another Time, an installation of 100 life-size figures on Crosby Beach, in Merseyside, became permanent after people campaigned on its behalf. Some have gone as far as adding clothes to the figures: one of the Water of Leith men has already been spotted sporting a bright pink bikini.

Installing the six figures in and around the river was a "complex logistical operation", according to Long. "The river is an important natural environment in the middle of the city and we were very conscious of our responsibility in that," he says. "We had to do pre-installation reports to make sure that there were no otters nesting near the sites of the sculptures, and the figure at the docks was installed slightly earlier so it did not disturb breeding seabirds."

The seeds of the commission began in 2004 when the SNGMA won the coveted Gulbenkian Museum of the Year Award for Charles Jencks's Landform, and the decision was taken to put the 100,000 prize money towards a "similarly inspirational" project in the gallery's grounds. Gormley, however, who has an interest in taking art beyond art galleries and into the public realm, decided to extend the project into the city. The first of the six figures will be partially buried in the garden of the SNGMA, and the last stands at the end of an abandoned pier in Leith docks, looking out to the horizon. The remaining four will stand at sites in between, in the water itself.

Gormley, 59, got to know Edinburgh when his son was at university in the city. He told The Scotsman: "I have always enjoyed the fact that we've got this river running through a very highly dense urban environment. The idea is to connect different parts of the city with this geological and botanical conduit and to relate it to the idea of culture and nature. The same cast is buried up to its neck in the ground at the museum and also facing out to sea and the open ocean, so it's also about freedom and containment, about settled life and the longing for wider horizons.

"Essentially (the six figures] are life moments that have been frozen in iron. That object is then placed within, and exposed to, the elements. It's a singular work that deals with time. It will rust, so it will have its own organic relationship with that exposure, and it asks where do human beings fit in the greater scheme of things? Yes, we have a city, but here we have a body that is related to the elemental conditions of life."

Gormley is one of the most accessible and popular of the current generation of contemporary artists, an ideal choice for the National Galleries of Scotland's first commission to be placed outside its own grounds. Last year, in One & Other, he invited 2,400 ordinary Britons, selected randomly by computer, to spend an hour on the vacant fourth plinth in Trafalgar Square. He has described the work as a portrait of contemporary Britain.

"Gormley is an artist who has really transformed how people view contemporary art in this country," says Philip Long. "His work has proved that contemporary art reaches a wider public.

"He wanted to draw attention to the Water of Leith by introducing a human figure into that; he wanted to make us look afresh at how people connect with that place."

Antony Gormley will give a talk at the Hawthornden Lecture Theatre at the National Gallery Complex, on Tuesday 22 June at 6pm. Tickets 8 (6 concessions)