The IMF has blocked the 190-million euro tranche because Belgrade changed the 2012 budget from previously agreed figures.
An IMF delegation on February 9 left Belgrade without a deal after the government of Prime Minister Mirko Cvetkovic refused to reverse the changes.
Serbia insists that the changes -- which provide for guarantees for loans to state-owned companies -- are not expenditures, while the IMF states the opposite.
Under the agreement with the IMF, Serbia's 2012 budget deficit must not exceed 4.25 percent of gross domestic product.
An IMF team would return for a new evaluation in mid-2012.
Compiled from agency reports