The figure falls short of the 65 billion euros Spanish Prime Minister Mariano Rajoy said on Wednesday would be generated through tax hikes and spending cuts aimed at convincing the EU and investors it is serious about reform.
The 8.6 billion euro shortfall will be covered by other measures such as new taxes on the energy sector which are expected to be announced later this month, El Pais said, citing government sources.
Of the 56.4 billion euros agreed so far, about 29 billion euros will come from changes to tax rates and 27 billion from spending cuts.
No one at the Treasury Ministry, which refused to provide a breakdown of the reform measures at a news conference on Friday, was immediately available to comment.
Spain needs to erase 65 billion euros from its public deficit in order to reach an EU target of 2.8 per cent by 2014.