Popping the cork on City Administration Centre's 40th birthday

It is known colloquially as the Wedding Cake, the Roundhouse, the Champagne Cork and the Shuttlecock, but no matter how it is described, Newcastle City Council's City Administration Centre has become an icon of the CBD skyline.

Friday 23 June marks exactly 40 years since the building was officially opened by then-Governor of NSW Sir Roden Cutler - an event that marked the culmination of years of planning and complex engineering.

Once home only to a row of tin sheds housing a sheet metal business, the site was earmarked as early as 1950 for development to ease the growing issue of overcrowding at City Hall.

Site excavation, which included digging several storeys down to create a basement car park, was complicated by the unusually high water table. It required construction of what amounted to an underground dam around its perimeter.

Newcastle Lord Mayor Nuatali Nelmes said the CAC had since become one of the city's architectural landmarks.

"So much has changed in Newcastle since the CAC was built," she said.

"It's testament to the building's original design that it still looks so striking and unique, 40 years after it first opened."

Newcastle City Council digital print coordinator Graham Barrie - one of the organisation's longest serving employees - had already been working for Council for 10 years when the CAC opened.

"Everyone was excited about having this round building there," he said. "It was this unique design and there was no other building in Newcastle like it."

"I've always called it the Roundhouse. Even back in the early 80s, our staff indoor soccer teams were called the Roundhouse Rebels and the Roundhouse Rats."