ROME — The Italian government and Venice officials have agreed on a plan to block giant cruise ships from steaming past the lagoon city’s iconic St. Mark’s Square and instead re-route them to a nearby industrial port.

The agreement reached Tuesday, the latest in a years-long debate and still subject to final details, seeks to balance the environmental concerns of Venice’s delicate ecosystem with tourism and maritime jobs.

Transport Minister Graziano Delrio said the plan, to be phased in over three-five years, calls for cruise ships over 55,000 tons to dock at the mainland’s Marghera port and avoid transiting through the Giudecca canal, one of the main waterways through Venice that empties into the St. Mark’s basin.

Environmental groups rejected it since it still allows polluting cruise ships to enter Venice’s lagoon.