BRASILIA , Brazil (AFP) - Brazilian President Dilma Rousseff on Friday raced to build support for reforms in response to nationwide protests as the head of world football hailed the Brazil-hosted Confederations Cup as the "best ever".

Ms Rousseff met members of civil society after a week of marathon talks with elected officials, union and party leaders to put the finishing touches on a proposed plebiscite on political reform she hopes to submit to Congress as early as Tuesday.

Meanwhile in Rio, Fifa president Sepp Blatter said the ongoing Confederations Cup - held against the backdrop of the worst social unrest in Brazil in 20 years - has been the "best ever".

"When we have a look on the pitch of football, it was easy to say that it was the best Confederations Cup that we have ever organised," he told a press conference two days before hosts Brazil are to face Spain in the tournament's final in Rio's Maracana stadium.

The dry run for next year's World Cup has seen hundreds of thousands take to the streets to protest against corruption, demand better public services and object to the US$15 billion (S$19 billion) price tag of the premier sporting events.

Many of the protests have been marred by violent clashes between small groups of protesters and police, but Mr Blatter said football had risen above the turmoil.

"The tournament was played in a situation where there was definitely social unrest, with protests and demonstrations, but finally, the football has played a positive part here," Mr Blatter said.

"Definitely football is going out from this competition with a clear message: yes, it was a good competition, and we are happy to be back here next year in the Fifa World Cup."

Ms Rousseff, scrambling to respond to the biggest crisis faced by her left-wing government since she assumed power in 2011, on Monday announced plans for a plebiscite on political reform.

Her mentor and predecessor Luiz Inacio Lula da Silva lent his support, hailing the plebiscite idea for "breaking the impasse on a crucial issue", which has been on the national agenda for years.

The demonstrations continued on Friday, albeit on a much smaller scale.

Protesters blocked traffic on several roads across the country and marches were scheduled in a dozen cities.

A major rally was planned in Rio on Sunday to coincide with the Brazil-Spain Confederations Cup final.

In an interview published on Friday, Fifa secretary general Jerome Valcke appeared slightly less hopeful than Mr Blatter regarding next year's football World Cup, the biggest sporting event on the planet.

"I hope that the turmoil which we are seeing in the streets will not continue until the World Cup," he told the Rio daily O Estado de Sao Paulo.

World Bank President Jim Yong Kim meanwhile told Agence France-Presse (AFP) on Thursday that no country in the world is immune from unrest arising from poverty and inequality.

"We have to recognise how much Brazil has done for the poorest," Mr Kim, a South Korea-born American, told AFP in Washington.

"Brazil has done a lot but there's still a lot of inequality left... Brazil really has to think hard about what it needs to do next for the next stage of economic growth."

On Thursday, Ms Rousseff met with her coalition partners to discuss her plans to reform campaign finance and the proportional representation voting system.

The government wants the political reform to be in place in time for next year's presidential elections, in which Ms Rousseff will seek another term.

The opposition supports a plebiscite but not the one suggested by Ms Rousseff ,which it has dismissed as "diversionary tactics".

After two years of weak economic growth and rising inflation, Ms Rousseff also faces budgetary constraints as she scrambles to meet the rising expectations of a newly-empowered population.

Protesters have won a number of concessions, with the Senate backing tougher penalties on corruption and scrapping a proposed constitutional amendment that sought to curb the investigative powers of independent public prosecutors.

And the Chamber of Deputies backed a bill that would allocate 75 per cent of oil royalties to education and 25 per cent to health.

"What Congress rushed to approve, and measures adopted by the central government and by the states, mean more spending at a time when the market is hinting that Brazil needs a fiscal adjustment," said Mr Ricardo Ribeiro, an analyst with the MGM consulting firm.

On Thursday the Central Bank lowered its growth forecast for this year from 3.1 per cent to 2.7 per cent and said it anticipated higher inflation of 6 per cent.