Brazil and FIFA on Thursday played down concern about sluggish World Cup preparations, with President Dilma Rousseff insisting stadiums would be ready.

After FIFA secretary-general Jerome Valcke warned Tuesday that Curitiba might be dropped as one of the 12 host cities for the tournament due to slack preparations, FIFA chief Sepp Blatter sounded a reassuring note after talks with Rousseff in Zurich.

"Confidence reigns. We now still have several months to go and we still need to make a few small adjustments here and there," Blatter said.

"I'm used to World Cups. There won't be any problem. In the end, everything will be fine in Brazil," he predicted.

FIFA initially set a firm December 31 deadline for all 12 of Brazil's venues to be completed but had to scrap that date with half of the stadiums still requiring work.

The World Cup kicks off on June 12 and ends on July 13.

Rousseff earlier this month countered criticism from Blatter over Brazil's tardy preparations for the event by insisting the country would prove able to host the "Cup of Cups".

On Thursday, she reiterated that pledge.

"The Brazilian government will do everything, and the stadiums will be ready...We will do everything to ensure that this will be the globe's most beautiful World Cup ever," the Brazilian leader said.

"That includes the stadiums, the airports, the ports and all the infrastructure needed for our country to properly host everyone who'll be coming to us."

Rousseff was in Switzerland to attend the World Economic Forum in the Alpine resort of Davos.

Blatter's secretary general Jerome Valcke meanwhile confirmed February 18 as the deadline for progress in the Curitiba stadium work, two days after threatening to drop the venue.

Valcke told a press conference at Rio's Maracana arena that FIFA now expected stadium delivery in late April or early May.

FIFA appears to have been swayed by Rousseff's assurances that all is being done to complete preparations on time.

Valcke said it would be a major challenge to change the plan for four games in Curitiba, saying It would prefer to see the stadium completed at the last minutes rather than to resort to a Plan B.

"Curitiba will not be excluded from the World Cup, I am absolutely certain," said Jose Maria Martin, president of Brazil's Local Organizing Committee.

But Valcke stressed "issues" remained.

"What will happen in Curitiba -- we are asking for a number of things to happen around the stadium. It is a challenge," Valcke told reporters.

"There is no easy solution -- the best one for Brazil is to make sure we can organize these four games in Curitiba," said Valcke, who angered Brazil last year in suggesting the hosts needed a "kick up the backside" to speed up preparations.

"We will look at what's happening in the stadium every minute of the day. There are issues -- as long as it's not finished there will always be issues," said Valcke.

Deputy Brazilian sports minister Luis Fernandes said Brazil would do everything it could to ensure Curitiba is kept as a venue.

He vowed to overhaul management of the construction team there and to determine if more workers could not be drafted to add an extra daily shift to speed things up.

"We believe once these measures are implemented we can guarantee delivery of the stadium," said Fernandes.

Fernandes pointed out there had been serious doubts over the northern city of Recife's readiness for last June's Confederations Cup -- a World Cup dress rehearsal -- but ultimately had delivered.

"Concern was voiced -- and yet the stadium was delivered."