A long-delayed flood barrier successfully protected Venice from a high tide for the first time today - seeing off threats the historic city could be submerged.

'Today, everything is dry. We stopped the sea,' city mayor Luigi Brugnaro told reporters after raising a glass in celebration with some of the engineers and officials responsible for the multi-billion euro project known as Mose.

'Lots of bad things have happened here, but now something wonderful has happened,' he said.

The network of 78 bright yellow barriers that guard the entrance to the delicate Venetian lagoon lifted from the sea bed as the tide, driven by strong winds and rain, started to climb.

City officials had forecast a tide of 4.27ft, well below the devastating 6.13ft tide that battered Venice last November, but enough to leave low-lying areas deep under water. 

Expecting the worst, workmen had laid out raised walkways in especially vulnerable places, including the often packed St. Mark's Square. In the event, the tide only amounted to 2.29ft, leaving the city's piazzas and pathways unscathed. 

'Today is an important day, an historic day because we should have been full of water by now and instead we are dry,' said Massimo Milanese, manager of the Lavena Cafe in St. Mark's Square.