The World Court has turned down a request by Uruguay to force Argentina to end blockades of vital roads and bridges between the neighbouring states in protest at a new Uruguayan paper mill.
"The court by 14 votes to one finds that the circumstances ... are not such as to require the exercise of its power," said judge Rosalyn Higgins.
Last December, Uruguay appealed to the court to force Argentina to end blockades of vital bridges between the two nations by protesters against the pulp mill under construction on the Uruguayan side of the river which separates the states.
Uruguay said the blockades were strangling its economy and would cost it hundreds of millions of dollars in lost trade and tourism, but Argentina rejected those accusations.
The World Court or International Court of Justice, the United Nations' highest court, was set up in 1946 to resolve disputes between states. Its rulings are final and cannot be appealed.