The Tripoli-based Libyan Audit Bureau (LAB) has said that the Central Bank's foreign reserves fell from $105.9 billion at the start of 2014 to just $76.6 billion at the end of the year.
In its report for 2014, the LAB warns that the dramatic fall in oil revenues, combined with continued spending, could mean that the economy will collapse in less than two years.
Oil revenues fell 30 percent to 20 billion Libyan dinars ($14.6 billion) in 2014, one-third of their 2010 levels.
The Central Bank (CBL), left in charge of Libya's finances in the absense of a budget from either of the two rival governments, is now paying only public salaries and subsidies on basic items such as bread and petrol.
The full 515-page report (in Arabic) can be downloaded here.