Flooding in Venice receded on Tuesday from record highs over the weekend that left much of the city under water, as four people were found dead from flooding due to heavy rains in Tuscany in central Italy.

The level of the water in Venice reached 149 centimetres on Sunday -- its highest level since 2008 -- sparking a red alert in the city, where hardy bathers were seen taking a dip in the flooded historic St Mark's Square.

The maximum highs forecast in Venice this week are 90 centimetres (35 inches) on Tuesday, 85 on Wednesday, 80 on Thursday and 60 on Friday.

This month's flooding has revived a controversy over the delay in completing a multi-billion euro (dollar) system of barriers around the Venice lagoon.

Meanwhile the toll mounted from flooding in central parts of the country.

Three of the victims were found in a car that fell off a bridge that collapsed due to the swollen current near the town of Manciano late on Monday.

The local prosecutor's office said that the three victims were employees of electricity operator Enel who were travelling to a flood-struck area.

The heavy rains also left a victim in Capalbio on the Tuscan coastline, where a 73-year-old was carried away in his car by a gush of water.

Local trains were disrupted across Tuscany and the local governor has asked for assistance from the army but the rain in Italy has eased and several regions were expected to lower alert levels later on Tuesday.