Venice plans to trial a reservation system for day-trippers, an official said Wednesday, in a bid to ease over-tourism as visitors flock back to the Italian city following the pandemic.

The pay-to-visit scheme will not cap tourist numbers but aims entice some people to visit during the low season by charging them less.

"We will start with an experimental phase during which the reservation will not be mandatory, but optional" and will cost nothing, Venice's deputy tourism councillor Simone Venturini told AFP.

Visitors just popping in for the day will be encouraged to sign up through incentives "such as discounts on museum admissions", he said. The start date will be announced in the coming weeks.

The system, which has been in the works for years, will become compulsory in 2023 and will see day-trippers pay between three and ten euros (around $3 to $10), depending on the season.

Visitors who sleep in Venice, already subject to the so-called tourist tax, will be exempt.

Life in the hugely popular watery city has slowly been returning to normal after the coronavirus pandemic, when the Grand Canal was emptied of gondolas as tourists disappeared.

Easter weekend drew a vast number of visitors, with 100,000 sleeping over nightly and some 40,000 others coming in for a few hours, to marvel at St. Marks or sigh at the Bridge of Sighs, said Venturini.

The sheer numbers cause long lines at vaporetto ferry stops or in front of museums, and overbooking in hotels. The crowds also make life difficult for the few locals who still live in the historic centre.

Venice's mayor Luigi Brugnaro, determined to save the city from becoming little more than a resort, said the reservation system was "the right road to take, for a more balanced management of tourism".

"We will be the first in the world to carry out this difficult experiment," he said on Twitter.

Once the reservation becomes mandatory, controls will be carried out at the bus and train stations, the two main access points to the city dubbed the "Serenissima".