The world and European champions have a host of corporate sponsors including German manufacturer Adidas, energy company Iberdrola, Movistar, the mobile phone unit of telecoms operator Telefonica, and carmaker Nissan.
The RFEF's latest gesture, which needs approval from the board of directors, means it will have turned down just under €5 million (£4m) it was entitled to for 2012, 2013 and 2014, according to the government sports council (CSD).
"It's yet another thoughtful gesture from (RFEF president) Angel Villar, whom I again thank personally for the sensitivity he has shown in these times when the rest of the federations need help," secretary of state for sport Miguel Cardenal said.
"Soccer, in this case the federation, is behaving like a big brother to the other sports and his proposal to the board for a third straight year needs to be brought to the public's attention," he added.
Many of Spain's smaller federations find it tough to attract commercial sponsors and rely heavily on public money.
With less cash available due to sweeping government budget cuts, concern has been mounting that performance and results will be affected over the longer term.