CARACAS, Dec 9 (Reuters) - Venezuela’s economy shrank by 4.2 percent in the first three quarters of 2014, an adviser to the country’s main opposition group said on Tuesday, after almost a year of official silence about the state of the OPEC nation’s economy.

The central bank has not published any GDP data for this year and has not revealed inflation figures since August’s 63.4 percent 12-month reading, spurring criticism that President Nicolas Maduro is hiding bad economic news.

“The central bank has not given figures but I’m going to give them to you,” Jose Guerra, a former central bank director who now works as an adviser to the opposition’s Democratic Unity coalition, told a news conference.

“GDP dropped by 4.4 percent in the first quarter, 4.4 percent in the second quarter and 3.5 percent in the third quarter,” he said, yielding a drop of 4.2 percent for the first nine months of the year.

Venezuela’s economy grew 1.3 percent in 2013.

Guerra said the 2014 data was discussed at a central bank board of directors meeting, but did not say how he got it.

He served as the central bank’s head of economic research but left in 2005, protesting interference by then President Hugo Chavez’s government.

The central bank did not immediately respond to an email seeking comment. The information ministry, which handles media requests for the finance ministry, also did not immediately respond to an email requesting comment.

Opposition leaders say currency controls that stimulate capital flight and frequent state takeovers of private businesses have weakened the country’s productive capacity.

Officials have blamed economic problems including soaring inflation on violent opposition protests earlier this year.

The economic woes, greatly exacerbated by the recent slump in oil prices to five-year lows, have spurred concerns Venezuela might default on foreign debt obligations.

Bonds fell sharply on Tuesday, with the benchmark global 2027 dropping 2.1 percent to a bid price of 48.646 with a yield of 20.887 percent.

Maduro has insisted the country will make all its debt payments and notes the ruling Socialist Party has never defaulted on its commitments to foreign creditors.

Default concerns have nonetheless pushed the spreads on Venezuelan bonds to the highest of any emerging market nation.

Venezuelan debt on average pays 23 percentage points more than comparable U.S. treasury bills - more than quadruple the spread of Iraq and triple that of Argentina, which is in default due to a legal battle with creditors. (Writing by Brian Ellsworth, editing by Andrew Cawthorne and Tom Brown)