Sydney Council’s plans to adorn the CBD with $8 million worth of sculptures variously described as “awe-inspiring” and “whimsical” have left few people indifferent.

"I thought, 'wow'," a beaming lord mayor Clover Moore said recalling her reaction when a panel of experts unveiled a final concept for a 50 to 75-metre high centrepiece “cloud” arch for George Street from a field of hundreds.

Other reactions were pithy too – but sprang from different emotions.

“Gigantic and stupid” were the kindest words leading sculptor Ron Robertson-Swann had for the three multimillion-dollar artworks. ''They're going to bore the pants off us.

“It’s a decorative arch,” he said. “It could be half that size and that would be generous. It’s not going to be an icon of Sydney.”

Architect David Vago was similarly scathing: “Would Michelangelo be turning in his grave if he knew that art now was just taking an object and making it giant?”

The $3.5 million installation, compared by the lord mayor to great world structures such as the Eiffel Tower, was designed by Japanese artist and Harvard critic Junya Ishigami.

The two other artworks include a $2.5 million three-storey high pavilion shaped like a milk crate for Belmore Park next to Central Station. And, for the Kent Street underpass, a $2.1 million installation featuring 60 handmade bronze birds.

Robertson-Swann labelled the milk-crate creation “seriously boring”.

But the choices had plenty of defenders among local critics. Museum of Contemporary Art head Elizabeth Ann Macgregor, who praised the arch and Ishigami’s ephemeral style, said: “It puts us on the international map.”

One councillor was heard to compare the metal white ribbon to Casper the Friendly Ghost when it was privately unveiled weeks ago. Other leading nickname contenders include the skipping rope and the dental floss.

But it was unclear what could be done if Sydney simply hated these bold ideas.

The question of how democratic and transparent the selection of public art ought to be has marred debate about the new installations which were meant to be secret until Tuesday morning.

Liberal councillor Edward Mandla called for the public to see and comment on the finalists.

Other councillors argued making losing designs public would discourage entrants who would no longer be able to enter them into other competitions.

The pieces will be completed in three to seven years and serve as a centrepiece for George Street in time for its transformation into a pedestrian boulevard and light-rail line late this decade. The final height of the arch will be designed after further technical analysis.

Cr Moore, sensitive to such criticisms, said that today was simply the beginning of a conversation about the artworks.

But when asked whether there was any conceivable way in which these plans would be changed, she dodged.

Just as with the public reaction to an expert panel’s choice of design for the Opera House in 1957, the public would learn to love these artworks, she said: “People know Sydney, they know the Opera House, they know the Harbour Bridge and in future they’ll know the cloud.”