SAO PAULO: President Dilma Rousseff has 38 percent of voter support ahead of her October re-election bid and would win a second-round runoff, a new poll by the IBOPE polling institute showed on Tuesday.

Her main challenger, Aecio Neves, has the backing of 22 percent of potential voters while Eduardo Campos has 8 percent, according to the survey broadcast on TV Globo.

In a second-round runoff vote, Rousseff would defeat Neves with 41 percent of the vote compared with his 33 percent, the survey found.

Two other polls in the past week have predicted a statistical tie.

The IBOPE poll surveyed 2,002 people from July 18-21 and has a margin of error of 2 percentage points.