By Malena Castaldi

MONTEVIDEO (Reuters) - Exit polls showed Uruguay's ruling leftist coalition candidate Tabare Vazquez with a strong lead in the country's presidential election on Sunday but falling short of a 50 percent majority required to win outright in the first round.

One poll by Consultora Factum showed the Broad Front's Vazquez winning 46 percent and Luis Lacalle Pou of the National Party with 31 percent. A second exit poll conducted by Equipos Consultores had Vazquez winning 44 percent and Lacalle Pou taking 33 percent.

If the trend is confirmed by the South American country's electoral court, it would pave the way for a tight second round on Nov. 30. Opinion polls ahead of Sunday's vote had shown Vazquez and Lacalle Pou neck-and-neck in a runoff.

Vazquez, 74, brought the ruling Broad Front to power in 2005 and his blend of pro-market economic policies and social welfare measures that slashed poverty rates won broad support but he was constitutionally barred from a second consecutive term.

Outgoing President Jose Mujica continued the model, which remains popular though many voters have become disenchanted with the scale of his liberal social reforms, including the legalization of marijuana production and distribution.

Vazquez has faced stiff competition from Lacalle Pou, 41, who has climbed steadily in polls since an unexpected victory in his party's primaries, campaigning on a platform for change.

(Additional reporting by Esteban Farat; Writing by Sarah Marsh; Editing by Kieran Murray, Richard Lough, Nick Zieminski and Jeffrey Benkoe)