According to the Ibope poll, the president opened a 14-point gap to the second-ranked candidate, Marina Silva. Rousseff has 39 percent of voting intentions, up from 37 percent in the previous poll, released last week.
The figures are similar to the Datafolha poll, released earlier on Tuesday.
Rousseff would beat Silva in an eventual second round by 42 percent to 38 percent. As the poll has a margin of error of two points, the two are technically tied.
Rousseff would also defeat Neves by 45-35 percent. In a second round between Silva and Neves, Silva would win by 38-34 percent, also a technical tie.
The Ibope poll was carried out among 3,010 electors from 203 towns in Brazil, between September 27th and September 29th.
Brazilians will cast their ballots on Sunday. If no single candidate receives an absolute majority over 50 percent, a runoff between the top two vote winners will be held on October 26th.