World football governing body FIFA has reiterated its concern at delays in the redevelopment of Rio de Janeiro's Maracana Stadium for the 2014 World Cup.

The iconic venue is still without a roof and turf as workers battle around the clock to finish the arena ahead of FIFA's April 15 deadline.

Maracana is scheduled to stage three FIFA Confederations Cup matches in June, including the tournament final.

FIFA originally gave the event's six venues a December deadline to complete refurbishment works but only Fortaleza's Castelao and Belo Horizonte's Mineirao are ready.

"The city which I will be visiting in two days is the one that worries me the most," FIFA secretary-general Jerome Valcke said during his tour of Recife's Arena Pernambuco on Tuesday.

Valcke was due to visit Bolo Horizonte on Wednesday and Rio de Janeiro on Thursday, where an inspection of the Maracana will be followed by a meeting with the local 2014 World Cup organizing committee.