About a quarter of state budget spending for the next three years is being kept secret by the government, Vedomosti reported Monday, citing the Gaidar Institute.
The size of undisclosed expenditure is 16.7 percent in 2014, 21.4 percent in 2015 and 24.8 percent in 2016, which equates to 9.68 trillion rubles ($300 billion), Lenta.ru reported.
The trend represents a rise from the average of 11.2 percent between 2005 and 2012.
The increase in undisclosed expenses partly stems from the growth of state spending in certain spheres, notably in defense, an unidentified senior Finance Ministry official said.
In 2014, almost 60 percent of expenses on national defense will be classified, as well as more than 28 percent for law enforcement agencies and almost 23 percent for community services.
Other areas with classified special purpose items include "nationwide issues," the national economy, education, culture, mass media, healthcare, social policy and physical education.
Statements that specify which items budget funds are spent on have also been made more general, which has "made life easier" for its authors but has "made control over the budget more difficult," said Vasily Zatsepin, a researcher from the institute.
Last year, Russia made it into the top 10 of the of the world rating Open Budget Index, getting 75 marks out of 100, and coming ahead of 170 other countries.