Venice has appealed to top European cruise ship destinations, from Amsterdam to Barcelona, Dubrovnik and Marseille, to unite in tackling the dangers and environmental impact of hulking liners, port authorities said Thursday.

The rallying cry for new rules to force companies to adapt their ships to the historical port cities that host them follows a collision between a cruiser and tourist boat in Venice that forced tourists to run for their lives.

The UNESCO World Heritage Site is also slowly sinking, with cruise ships blamed for eroding the floating city's foundations.

"I have written to all European cities that share our experience with cruise tourism, and that find themselves having to balance economic development with environmental sustainability," Pino Musolino, chairman of the northern Adriatic Sea port authority, said in statement.

"The growing size of vessels, their environmental impacts on the areas surrounding the ports and the 'burden' that the increasing number of tourists... are creating a situation of conflict," he said in a letter to eight fellow port authorities.

He called on them to "join forces" to oblige companies to "launch ships compatible with our structures and the environment".

In June, the giant 13-deck MSC Opera rammed into a dockside in Venice and knocked into a small tourist boat, injuring four people and sending others on the pier running for safety.

A month later, the 12-deck Costa Deliziosa, nearly 300 meters long, very narrowly missed a yacht while being towed out of Venice in stormy conditions.

Monster liners

The accident and near-miss reignited a long-running row over the damage caused to the city and its fragile ecosystem by cruise ships that sail exceptionally close to the shore.

Critics say the waves the ships create are eroding the foundations of the lagoon city, which regularly floods, leaving sites such as Saint Mark's Square underwater.

The "Serenissima", as the city is known, is not alone in suffering from mass cruise tourism.

In 2017, hugely popular Dubrovnik -- another UNESCO World Heritage site -- became synonymous with the cruise "overtourism" scourge, showing up on lists of destinations to avoid.

Marseille has wrestled with increased smog in recent years as it seeks to attract more lucrative cruise tourism.

And Bruges has said it plans to limit the number of cruise ships docking at the nearby port of Zeebrugge in a bid to curb the masses of day-trippers that descend on the so-called "Venice of the North."

The northern Adriatic Sea port authority in Venice said it had already received a positive response to its appeal from Barcelona, Palma and Marseille, and expected others to follow.

About 30 million people worldwide are expected to go on a cruise this year, up nearly 70 percent from a decade ago, according to the Cruise Lines International Association.

The rising number of monster liners, often hundreds of meters long and several stories high, has increased concerns about environmental damage -- including acid rain and damage to aquatic species -- as well as health risks.