Already suffering due to a series of reductions in state subsidies in recent years, federations have been hit with fresh cuts of around 50 percent forced on the government by the economic crisis.
In an interview with sports daily As published on Wednesday, Blanco said the performance of Spanish athletes at the 2016 Olympics in Rio de Janeiro would suffer unless swift action was taken to boost private sponsorship.
"Sport needs fast solutions because an Olympic cycle has just ended but another is beginning and with 50 percent less in public funds," he told the paper.
"If there is no state cash and no sponsor you cannot progress and if we continue along the same path it will lead to the precipice."
Relatively wealthy federations such as football and basketball, who have a host of corporate sponsors lured by some spectacular results in recent years, will not be much affected by the latest austerity measures.
The football federation, flush with cash thanks to Spain's triumphs at the 2008 and 2012 European Championships and the 2010 World Cup, has foregone its two most recent subsidies of around 3 million euros each, about three percent of its total budget of just over 100 million euros.
By contrast, public funds accounted for 46 percent of the athletics federation's budget last year and more than 50 percent of the budgets for cycling and swimming.
Spanish track and field athletes have performed particularly poorly in recent years and failed to win a single Olympic medal in Beijing four years ago or in London this year.
"We cannot allow sport to collapse, because if nothing changes it will collapse," Blanco said.
Budget cuts by Spain's regions, who fund sports and sporting facilities at a local level, will mean young athletes struggling to come through will also be affected and not just the elite, he added.
"We have to find a way to change the system. Sports cannot depend only on the government but it has to keep developing."