Brasilia, Brazil: Brazilian President Dilma Rousseff formally launched her re-election bid Saturday, leading in opinion polls despite lingering discontent over World Cup costs.

Rousseff’s leftist Workers Party (PT) approved her candidacy in a voice vote of 800 members meeting at a convention in Brasilia, with the popular former president Luiz Inacio Lula da Silva on hand.

“It is time to move forward, it is time to make more changes,” the 66-year-old leader told her party in a hotel convention hall decorated with red stars and posters of the president.

Rousseff’s popularity has fallen but she leads her rivals ahead of the October presidential election, with 39 per cent of voters backing her candidacy, a survey by pollsters CNI Ibope showed Thursday.

The former guerrilla member, who was jailed and tortured during the 1964-1985 military dictatorship, is well ahead of Social Democratic Senator Aecio Neves, with 21 per cent, and socialist ex-governor Eduardo Campos, a former ally, with 10 per cent.

The PT convention turned into a defence of the World Cup, with promises of changes in a new Rousseff administration following protests over hosting the tournament that began June 12 and ends July 13.

Party members chanted “one, two, three, Dilma one more time” and “Lula, warrior of the Brazilian people.”

“The World Cup is scoring goals against the pessimists, those who said it would not take place,” Rousseff said.

Some voices within the party called on Lula to run for president as Rousseff’s popularity fell, but the former leader, who left office with an 80 per cent approval rating, has backed his successor.

“Many people have this feeling. But everything has its moment. Lula himself told us that she was the candidate. It’s important we vote for her,” said Nadia Araujo, 47, a PT member who was unable to enter the packed convention.

Brazilians held massive demonstrations during last year’s Confederations Cup, a warm-up to the main football event, to protest the World Cup’s $11 billion (Dh40 billion) price tag and demand better public services.

The public frustration coincides with a cooling economy.

Once boasting red-hot growth, Brazil’s gross domestic product rose by just 0.2 per cent in the first quarter and is forecast to expand by 1.63 per cent this year.

The protest movement has lost some steam, however, drawing smaller crowds during the World Cup but with sporadic clashes between riot police and masked radical protesters.

The anger seeped into the opening game as a crowd of fans chanted insults against Rousseff when she attended the match between Brazil and Croatia with a dozen foreign leaders.

Lula, who secured the World Cup when he was president from 2003-2010, defended the tournament, saying the stadiums exceeded expectations.

“The stadiums are all inaugurated and of such quality to make any Englishman die of envy,” he said, in a veiled criticism of British media concerns about the state of the pitch in Manaus.

For her part, Rousseff renewed her call for a referendum on a reform of the political system, one of the protesters’ demands.

She listed the social, economic and political actions taken by her government and said Brazilians want changes to continue “in the hands of those who showed that they have the capacity” to undertake them.

Her vice president, Michel Temer of the centre left PMDB party, also attended the convention. But another ally, the Brazilian Labor Party, confirmed it was now backing Neves.