Revenue collections were down 5.6% year-on-year to 923.78 billion baht from October 2013 to March 2014, said Somchai Sajjapongse, director-general of the Finance Ministry's Fiscal Policy Office.
The major cause was lower auto excise tax collections as demand slowed after the government's first-time car buyer scheme ended. The base last year was also padded by the one-time revenue from the 3G 2.1-gigahertz frequency auctions of 20.84 billion baht.
Budget disbursements rose by 0.9% to 1.38 trillion baht, resulting in a budget deficit of 460.32 billion baht.
When taking into consideration an off-budget deficit of 60.10 billion baht, cash balance deficit was 520.42 billion baht, which the government borrowed 130.16 billion baht to offset, resulting in total cash balance deficit of 390.26 billion.
Treasury reserves as of the end of March stood at 213.67 billion baht.
"While revenue collections were affected by the economic slowdown in the first half, high treasury reserves at more than 200 billion baht will help boost the economy through budget disbursements in the remaining months of fiscal 2014.