The ruling Workers Party is yet to select a candidate for 2010, when Lula will leave office after two consecutive terms.

"Even though he can't run for re-election, [Lula] will be a kingmaker in the 2010 presidential elections," Erasto Almeida, an analyst for the Eurasia Group, a New York-based consulting company, said.

President's popularity

Lula's popularity has increased as Brazil enjoys an extended economic boom that has raised salaries and helped lift millions out of poverty.

"[The president's] approval ratings have reached a record high, leading pro-government candidates to structure their campaigns trying to associate themselves with the president," he said.

A survey conducted by Datafolha, a market research firm, reported that Lula's approval rating of 64 per cent is the highest for any president since 1989, when an election was held after a 20-year military dictatorship.

Lula's party is seeking to exploit his popularity to wrest control of more mayorships, especially in 26 state capitals.

Vladimir Jorge, a political sociology professor at the Rio de Janeiro Catholic University, said: "If a party elects a significant number of mayors, it will have an electoral machine working in its favour in the next two years, doing work that will reflect positively for the party's presidential candidate."

The Workers Party "will at least maintain the strength it has now, and maybe add some important cities, like Sao Paulo", Jorge said.

The party won 411 mayorships four years ago, up from 187 in 2000.