The revised figures represent a nearly 5 percent increase from the ministry's 2010 estimate of 143 billion barrels.
According to Oil Ministry spokesman Assem Jihad, the higher figures are the result of increased prospecting work in the country's oil sector over the past two years, adding that the revised estimates do not include the figures for Iraq's semi-autonomous Kurdish region.
Kurdish officials assert that the region under their political control contains 45 billion barrels, although the figure cannot be confirmed independently, the Arab News reported on Friday.
Iraq is OPEC's second largest oil producer after Saudi Arabia, but the nation has been struggling to increase is output over the past decade in the wake of the 2003 U.S.-led invasion that toppled Saddam Hussein..
Oil revenues currently nearly 95 percent of Iraq's budget.