BRASILIA (Reuters) - Opposition candidate Marina Silva has increased her lead slightly over President Dilma Rousseff in an expected second-round runoff to Brazil's election next month, a new poll showed on Tuesday.
The survey by the Ibope polling firm said Silva's support among voters in a simulated runoff was unchanged at 43 percent, but Rousseff has slipped two percentage points to 40 percent since the previous poll last week.
In first-round voting, scheduled for Oct. 5, Rousseff has 36 percent voter support and Silva 30 percent, compared with 39 percent for Rousseff and 31 percent for Silva in the previous Ibope poll. Support for centrist candidate Aecio Neves has risen to 19 percent from 15 percent.
The Rousseff administration's approval rating has slipped to 37 percent from 38 percent in the earlier poll.
The new Ibope poll surveyed 3,010 respondents nationwide between Sept 11-16 and has a margin of error of plus or minus two percentage points. It was commissioned by media conglomerate Globo Comunicações and was broadcast on TV Globo nightly news program.
(Reporting by Anthony Boadle; Editing by Ken Wills)