Cruise liner Holland America Line and trip organiser RSVP Vacations told the 2,100 holiday-makers aboard the MS Nieuw Amsterdam ship that the July 1 visit to Casablanca had been cancelled.
"Our port agent in Casablanca has advised us that authorities in Morocco have -- despite previous confirmations -- now denied our scheduled visit," the two companies said in a letter tweeted to news organizations by passengers of the ship.
"For all of us, this is a very disappointing development," they added. "It was ultimately the decision by local authorities in Morocco that has necessitated us to adjust our plans."
The Casablanca visit was supposed to be the first and the only non-European leg of a week-long journey for the cruise liner, which sailed from Barcelona on Friday with mostly American and European passengers.
Morocco's Tourism Minister Lahcen Haddad said no official decision had been made to prevent the ship from stopping in Morocco.
"We don't ban cruise ships here and we never ask our visitors about their sexual preferences," he told Reuters. Asked if the MS Nieuw Amsterdam could still visit Morocco, he said: "They can if the organisers want to".Morocco's law criminalizing sex between men with jail sentences of between six months and three years and fines.