Exceptionally high tidal waters have surged through Venice again.

It prompted the mayor to close St Mark’s Square and call for more donations for repairs just three days after the Italian lagoon city suffered its worst flooding in 50 years.

The high tide peaked at five feet above sea level just before noon on Friday, flooding most of the historic World Heritage city’s centre.

Venice mayor Luigi Brugnaro said the damage is estimated at hundreds of millions of euros and blamed climate change for the “dramatic situation”.

He also called for the speedy completion of the city’s long-delayed Moses flood defence project.

Mr Brugnaro said he was forced to ask police to block off St Mark’s Square on Friday, which was covered in knee-high water. Workers in high boots removed the platforms used by the public to cross the famous square without getting wet.

Venice saw its second-worst flooding on record on Tuesday when water levels reached more than six feet above sea level.

That prompted the Italian government to declare a state of emergency on Thursday, approving 20 million euros to help Venice repair the most urgent damage.

Venice flooding
Workers carry wooden boards to create a bridge in Venice (Luca Bruno/AP)

“Venice is the pride of all of Italy,” Mr Brugnaro said. “Venice is everyone’s heritage, unique in the world. Thanks to your help, Venice will shine again.”

Venice, a lagoon city built amid a system of canals, is particularly vulnerable to a combination of rising sea levels due to climate change coupled with the city’s well-documented sinking into the mud. The sea level in Venice is four inches higher than it was 50 years ago, according to the city’s tide office.

More than 50 churches have reported damage from the tides, culture minister Dario Franceschini said as he inspected the city.

Carabinieri officers from the corps’ world-renowned and highly trained squad of art experts were being deployed to map damage to art treasures, a job that is expected to take some time.

Venice flooding
A man stands in front of a shop in a flooded St Mark’s Square in Venice (Luca Bruno/AP)

The Italian Space Agency said it was studying radar data from satellites to detect any signs that Venice bell towers may have shifted or that their foundations might have weakened as they were buffeted by the fast-rising waters.

Many people were rising to the challenge of saving Venice’s many treasures.

University students in Venice rushed to libraries and other institutions filled with books and manuscripts to help shift the material to higher levels.

The Italian Society of Authors and Editors, which said Venice’s book stores and libraries were “gravely damaged” by the high water, launched a fundraising campaign.

Pitching for donations from Italy and abroad, the group said it was important to “take the side of those who every day are on the front lines for the defence of Italian culture”.