Vietnam’s foreign-exchange reserves have declined to less than two-and-a-half-months worth of imports, the International Monetary Fund said Thursday.

A decline in foreign-exchange reserves has increased the risk of a balance of payments crisis in Vietnam, Moody’s Economy.com said in a Dec. 1 report, which estimated reserves at about $16.5 billion, less than three months of import cover. The IMF statement, released at a meeting in Hanoi Thursday, didn’t give a figure for foreign exchange reserves.

The easing of monetary and fiscal policy under Vietnam’s stimulus program contributed to “significant” trade deficits, during a time when Vietnamese shifted their savings toward gold and other foreign-currency assets, the IMF said. As a result, the dong weakened.

“As the authorities have defended the dong, gross international reserves have fallen to below two-and-a-half months of imports,” said Shogo Ishii, assistant director of the IMF’s Asia and Pacific Department, in remarks prepared for delivery at the meeting. “Access to foreign exchange has been difficult, imposing costs on enterprises and adversely affecting investor sentiment toward Vietnam more generally.”

Vietnam’s foreign exchange reserves are more than $16 billion, State Bank of Vietnam Deputy Governor Nguyen Van Binh told journalists Thursday in Hanoi.

“It’s enough for the central bank to intervene to stabilise the market,” Binh said.

Vietnam’s central bank values its current level of foreign- exchange reserves as sufficient to cover more than three months of imports, Binh said. The IMF’s estimates on import cover are based on the agency’s projections, according to Benedict Bingham, the agency’s senior resident representative in Vietnam.

“If foreign direct investment and official development assistance flows remain firm, this would allow a modest recovery of gross international reserves in 2010,” Ishii of the IMF said in Thursday’s statement.