Dumping into the Baltic Sea by large cruise liners is endangering the coastal waters of Sweden, an environmental report says.

The World Wide Fund for Nature said in a recent report that passenger liners have been disposing of toilet waste and other materials in the Baltic Sea because many regional ports are ill-equipped to handle large amounts of ship waste, The Local said Friday.

The study said harbors in the Swedish cities of Stockholm and Visby, along with a port in the Finnish capital of Helsinki, are the only regional ports capable of adequately handling such cruise ship byproducts.

"It is not fair that large harbors and cities earn money from the cruise ship industry without putting in place satisfactory methods for handling their waste" Asa Andersson, WWF's head of Baltic program, said in a statement.

"We think that a part of this income should be used to improve harbor facilities to offer effective handling of waste water."

The environmental group said the cruise ship dumping has resulted in an increase in Baltic Sea nutrient levels, which can bring about environmental problems, The Local reported.