Rome mayor asks residents not to waste water as several Italian regions hit by severe drought.

The Lazio region around Rome is set to declare a state of emergency as an ongoing drought raises the prospect of water rationing in Italy's capital this summer.

Describing the situation as "serious", Lazio governor Nicola Zingaretti told Italian news agency ANSA that he will ask all mayors in the region to introduce water-saving measures.

As the river Tiber's water levels drop by a metre compared to this time last year, Rome's mayor Roberto Gualtieri stressed that at present there were no plans for rationing but advised the city's residents not to waste water.

Northern Italy is currently grappling with a severe drought which threatens the agriculture sector and has seen the river Po hit its lowest level in 70 years.

On Tuesday Italy's health undersecretary Andrea Costa indicated that the government is set to declare a state of emergency in the regions worst hit by the drought, ANSA reports.

Remains of the ancient Pons Neronianus or Bridge of Nero become visible as water levels drop in Rome’s river Tiber. https://t.co/s0bqJziErF

— Wanted in Rome (@wantedinrome) June 20, 2022

The head of the Tevere Basin authority, Erasmo D'Angelis, told ANSA that since the last drought in the summer of 2017, Rome's water authority ACEA had improved the city's poor record of leaking pipes, from 43 per cent down to 28 per cent.

"The climate is changing and we too must change", D'Angelis said, adding that currently the worst affected area in Lazio is the Viterbo province north of Rome.

Local media posted images of people walking on the Tiber river bed in north Rome while near the Vatican the remains of the ancient Bridge of Nero surfaced with the recent drop in water levels.

Photo ANSA Riccardo Antimiani