The stadium missed FIFA's initial December 31 deadline for completion and was considered to be so far behind schedule that a four-week ultimatum to accelerate construction was issued by general secretary Jerome Valcke last month.
"Curitiba confirmed as World Cup venue, based on the financial guarantees, the commitment by all stakeholders & progress made," a post on the governing body's Twitter account read.
"It's a race against a very tight timeline. Collective effort by all stakeholders involved in Curitiba must continue at highest pace."
Iran's clash with Nigeria is scheduled to be the first game to be held at the arena on June 16, with defending champions Spain travelling to Curitiba to take on Australia seven days later.
Brazil's preparations for the World Cup have been beset by construction problems, while protests over the cost of staging the tournament and fatal accidents at the venues in Manaus, Sao Paulo and Brasilia have also marred the build-up.
