LISBON, Jan 18 - Portuguese voters queued at polling stations on Sunday to elect a new president, with opinion surveys showing three candidates, including the leader of the far-right Cheap party, nearly tied for a spot in a likely top-two runoff.

In the five decades since Portugal threw off its fascist dictatorship, a presidential election has only once before - in 1986 - required a runoff, highlighting how fragmented the political landscape has become with the rise of the far-right and voter disenchantment with mainstream parties.