A coalition of leftist elements is predicted to win Uruguay's presidential election on Sunday - ending the conservative parties' dominance of more than 170 years.

Public opinion polls suggest Tabare Vazquez of the Broad Party will win more than 50 percent of the vote, giving him a first-round victory over the ruling Colorado Party's Guillermo Stirling and the right-wing National Party's Jorge Larranaga.

The latter two political groups have held the presidency since Uruguay gained independence from Spain in the early 19th century.

The Broad Party consists of leftist forces including moderates, radicals and ex-guerilla leaders. Their candidate is a cancer specialist and the former mayor of Uruguay's capital city of Montevideo.

Uruguay will have a run-off election next month if none of the candidates wins a majority.