Gross international reserves, or GIR, posted a decline to $98.7 billion in September from $99.6 billion in August due to government's higher foreign debt payments and the depreciation of gold, based on the preliminary data from the Bangko Sentral ng Pilipinas, or BSP.

The September level provided the government more than enough external liquidity, according to the central bank.

"This is equivalent to 7.3 months' worth of imports of goods and payments of services and primary income. Moreover, it is also about 5.7 times the country's short-term external debt based on original maturity and 3.6 times based on residual maturity," a BSP statement read.

GIR consists of gold, foreign exchange, foreign investments, reserves with the International Monetary Fund, or IMF, and special drawing rights.

The country seeks to maintain a GIR level that is equivalent to at least three-months' worth of imports to be considered adequate.

Net reserves down slightly
Similarly, the net international reserves or NIR decreased by $0.8 billion to $98.7 billion from $99.5 billion month-on-month.

The Philippines' external debt-to-GDP ratio at 28.5 percent as of the second quarter, the highest in at least a decade. But this was somewhat offset by the faster growth in GDP that led to a bigger GDP base/denominator.

NIR is the difference between the BSP's reserve assets or GIR and reserve liabilities, which consists of short-term foreign debt, and credit and loans from the IMF.

"The Philippines' external debt-to-GDP ratio at 28.5 percent as of the second quarter, the highest in at least a decade. But this was somewhat offset by the faster growth in GDP that led to a bigger GDP base/denominator" Ricafort explained.