Top Italian architect Paolo Portoghesi on Thursday became the latest cultural heavyweight to slam Rome's new home for the Roman Empire's most famous peace symbol, the Ara Pacis.

Portoghesi, whose credits include famed squares in Russia, France and Germany as well as two of Europe's biggest mosques, in Rome and Strasbourg, called the Ara Pacis museum, designed amid fierce polemics by US architect Richard Meier, "all wrong".

"It's wrong because it's four times the size of the previous building and it has no link to its surroundings," Portoghesi said during a lecture.

"It's incredible how Italy manages to get great architects like Meier to make terrible projects".

"Faced with the complexity of Rome and the Ara Pacis, Meier, whom I respect, ended up bewildered, stripped to his underwear," said the 75-year-old Portoghesi. Meier's large box-like home for the Roman monument has spurred recurrent criticism.

Two months ago US artist-filmmaker Julian Schnabel, in Rome for a show, called it "an air-conditioning unit".

Schnabel was flanked by a delighted Vittorio Sgarbi, the outspoken art critic, now Milan cultural chief, who once urged students to bomb the building and accused the American architect of "knowing Rome like I know Tibet".

Up to and even after its unveiling last year, Meier's minimalist but massive construction has been slated.

The criticism was so fierce that the famed 72-year-old architect was forced to change the project on several occasions - and even now Rome has opened bidding for ways to try to meld it into its surroundings.

As recently as last year, right-wing critics were insisting the Meier building should come down and be replaced by a simple showcase like the Fascist-era building Meier knocked down.

A year ago, then premier, now opposition leader Silvio Berlusconi rekindled the polemics by calling the museum "monstrous".

DECADE OF POLEMICS AND ALTERATIONS.

The sleek stone-and-glass complex - central Rome's first piece of modern architecture since Fascist days - was unveiled last year on Rome's legendary birth date of April 21 after a turbulent decade of polemics and alterations.

Mayor Walter Veltroni, an ex-Communist cinephile who has pledged to renew Rome's skyline, has championed Meier's modernist showcase since he was first elected six years ago.

But it met with fierce opposition from conservatives.

Sgarbi, Berlusconi's culture undersecretary from 2001 to 2003, burned a model of the building and punned that Meier was set on turning the Ara Pacis into a 'bara Pacis' (coffin of peace).

Italian 'name' architects cited the work as an example of alleged moves to 'Los Angelise' Rome.

Professional architecture critics have been split, with some hailing it as a welcome piece of understated modernism in a florid Baroque city, and others as wholly out of step with its surroundings.

Unbeknownst to many, Meier already had another Rome work under his belt - a 2003 church about six miles from the city centre which has met with acclaim from locals and critics.

A recipient of architecture's prime laurel, the Pritzker Prize, in 1985, Meier is perhaps best known for the Getty Center in Los Angeles.

His other credits include Barcelona's Museum of Contemporary Art and Frankfurt's Museum of the Arts.