Venice - French fashion designer Pierre Cardin's billion-euro (dollar) plan to build a giant tower on an industrial site in the Venice lagoon is causing a stir in a city with a proud architectural heritage.

While Venice mayor Giorgio Orsoni has given the project the go-ahead, some residents are up in arms and say the initiative is part of a set of policies that are increasingly turning Venice into a playground for wealthy foreigners.

And conservationists are cautioning that the contemporary design tower - a complex that would include luxury apartments, hotels, restaurants, education centres and sports facilities - could mar the Venice skyline forever.

"You cannot just turn up and decide to do something that makes no sense at all," said Alvise Benedetti, deputy head of the Venice section of Italia Nostra, a national association set up to defend the country's many monuments.

"Venice should be respected - it is a city with more than a thousand years of history," said Benedetti, a history professor, pointing out to an iconic view of the Rialto bridge on the Grand Canal that is renowned the world over.

A few steps away in a vast office decorated with frescoes, Orsoni is keen to stress that the tower will not be in the historic part of Venice but in an abandoned port area that is already an eyesore for anyone looking that way.

"We can see so much ugliness from Venice, like industrial chimneys. I think seeing the Palais Lumiere would be far nicer," the mayor told AFP.

"Apart from that, Venice has always innovated over the centuries. It has always been able to make leaps ahead and innovate in architecture," he said.

Cardin, who was born in the Venice region before emigrating to France, is no stranger to innovation seen in his visionary designs in the 1960s.

But the 90-year-old fashion maestro realises that winning over the people of Venice will be no mean feat and he visited the city himself on Monday to outline the 255-metre (837-foot) project and open an exhibition about it.

"I want to offer Venice a big garden for eternity," Cardin said.

He said he wanted the project completed in time for the Milan Expo in 2015, building on a 40-hectare lot currently occupied by some abandoned warehouses that would first have to be cleaned of industrial chemicals before building.

The complex is made up of six giant discs held up by three towers of different heights and is referred to by its designers as a "vertical city".

The budget is estimated at between 1.5 billion and 2.0 billion euros (S$2.4 billion to $3.1 billion) with part of the funds coming from Cardin himself and part coming from the pre-construction sale of luxury condos.

"This project will give work to a minimum of 5,000 workers," said Cardin, who has put his nephew, Rodrigo Basilicati, in charge of the project.

Asked by AFP why he had chosen Venice, Cardin said it was because of his Italian roots and added: "There is no space in Paris."

Cardin also defended himself against criticism from local conservationists saying that the tower "will not be visible from Venice".