A cruise ship crash in Venice has reignited calls for large vessels to be banned from the city's Giudecca canal. Four people were injured on Sunday when the MSC Opera - a 275m long (900ft) ship - collided with a dock and a small tourist boat after losing control. Critics say such ships pose a conservation risk to the lagoon city, pollute its waters and mar its beauty. Ministers said the crash proved the need for a ban on liners, and that they were working to resolve the problem. "What happened in the port of Venice is confirmation of what we have been saying for some time," Environment Minister Sergio Costa wrote on Twitter (in Italian). "Cruise ships must not sail down the Giudecca. We have been working on moving them for months now... and are nearing a solution." Infrastructure Minister Danilo Toninelli agreed, writing on Twitter (in Italian) that the incident was proof that big ships should not travel on the Giudecca. "After many years of inertia, we are finally close to a definitive solution to protect both the lagoon and tourism," he said. The Giudecca, which leads to the popular St Mark's Square, is one of Venice's major waterways. Critics say waves created by cruise ships on the canal erode the foundations of the city, which regularly suffers from flooding. Some have also complained that they detract from the beauty of Venice's historic sites and bring too many tourists. Venice's port authority called for action to resolve the issue of high cruise ship traffic. "Now is the time to handle the situation... to work to understand what happened and to find solution, once and for all," Pino Musolino, president of the North Adriatic Sea Port Authority wrote on Twitter (in Italian). The government has previously tried to resolve the cruise ship debate. In 2013, it banned ships weighing more than 96,000 tonnes from the Giudecca canal but the legislation was later overturned. In 2017, the government announced that it would divert larger ships away from the historic centre. However, the plans were expected to take four years to come into force. Venice Mayor Luigi Brugnaro on Sunday urged immediate action to open the alternative channel, known as the Vittorio Emanuele.