BRASILIA - Re-elected Brazilian President Dilma Rousseff on Sunday called for national unity and vowed to reinvigorate her country's economy and advance political reform during her second term.

"I call on all Brazilians without exception to unite for the future of the country," she told supporters in a victory speech here, adding that she is "open to dialogue".

"Some words dominated this campaign. The most frequently uttered was change. The most common theme was reform," she said. "I have been reelected president to make the major changes Brazilians are demanding."

Faced with an underwhelming performance in recent years of the Brazilian economy, the world's seventh largest, the president vowed to take special moves to boost her country's economic recovery.

"I want to be a much better president than I have been until now," she said.

Rousseff, 66, garnered about 51.6 percent of the vote in Sunday's run-off with opposition candidate Aecio Neves, which was believed to be the most bitterly contested presidential race in the South American country in two decades.