Three presidential candidates were vying for the votes of 2.5 million Uruguayan voters as polling stations opened Sunday to determine the composition of the next parliament and occupant of the country's highest office. Tabare Vazquez, from the leftist Frente Amplios, held a substantial lead in public opinion surveys going into the election, and could poll the required 50 per cent majority to gain the presidency without a runoff vote. Two conservative candidates, Jorge Larranaga and Guillermo Stirling, were far behind Vazquez in pre-election polls. Voters also faced a controversial referendum on whether to privatize the utility responsible for water supply.