The River Po, which runs for more than 650km (403 miles) from west to east across the north of the country, is running dry following an early summer heatwave, compounded by a lack of winter snow.

Waves from the Adriatic Sea have been crashing through anti-salt barriers and pushing downstream, making irrigation even more difficult for farmers already struggling against the high temperatures.

"Saltwater enters the water table," said director of Reclaiming the Po, Giancarlo Mantovani.

"There are parts of the fields with no plants and others where they grow regularly," he added.

"If there is no rain in the next 10 or 15 days, the crops that are not yet lost will be gone. At this stage, we are progressively losing the harvest."

In the province of Pavia, near Milan, farmer Luigi Ferraris said the crisis could continue for at least two years.

"Rice is harvested in September and October," he said. "We still have July and August ahead of us - two hot months - my worry is that if it doesn't rain...

"I am not saying it's a catastrophe, but we are nearly there."

In neighbouring Austria, a civil emergency has been declared after villages in the southern state of Carinthia were cut off by mudslides and flooding caused by heavy rainfall.

Local media reported that streams had burst their banks and mud had buried homes up to the first floor.

District captain Bernd Riepan said two people were missing, including someone who was reportedly in their car when it was swept away in the floodwater.

Public broadcaster ORF reported that residents of Treffen and Arriach were told to seek safety in the upper levels of their houses.

Several people who were trapped in their homes had to be airlifted to safety using helicopters.

Mayor of Arriach, Gerald Ebner, said the town had been cut off from the outside world.

"All connecting roads have been washed away," he commented.

He added that they were waiting for the army to bring heavy equipment to help make the roads passable again and to reach cut off households.