The Spanish giants are planning a two-match tour of Asia after the World Cup finals but construction work for the scheme to turn the 55,000-capacity arena into a "Sports Hub" would leave Singapore without a ground big enough to host them.
"Within the next week, we have to find out if we can have the National Stadium or else it will simply be too late to plan this," Jon Collins of football consulting firm Football Asia told the Today newspaper.
"A lot of Asian countries are keen to have them, Vietnam is bidding heavily to have them and is willing to pay 2.5 million euros. We will do everything in our power to see if we can get the venue to make it happen."
Singapore does have another venue, a huge floating platform at Marina Bay, but the revenue from a smaller crowd would not sustain a visit from the Catalan club, Collins added.
"To have 27,000 people watch a big club like Barcelona does not make financial sense," he said. "You need 40,000 to 50,000 people to make it viable, and only the National Stadium can hold such a crowd."
Lucrative pre-season tours of Asia by top European clubs have become commonplace in the last few years with Manchester United the major visitors last year.
Barcelona played matches in Beijing, Yokohama, Japan and Hong Kong on their last trip to the continent in 2007.
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