Former prime minister Najib Abdul Razak is alarmed over the state of Malaysia's international reserves, saying that there are insufficient funds to service short-term debts.

Bank Negara earlier today said that its international reserves had eased to US$101.7 billion, which is sufficient to finance 7.5 months of retained imports and was 0.9 times the short-term external debt.

"My concern is about the 0.9 times to short-term external debt... being below 1.0 means our reserves are insufficient to pay all our foreign short-term debts when it is called up.

"This is a new risk to the country. It means we owe foreigners US$100 (for example) and we only have foreign currency worth US$90 to pay it back.

"(Finance Minister) Lim Guan Eng, should take note," Najib said on Facebook today.

Najib said he had never seen the reserve to short-term external debt fall below 1.0 before the 14th general election.

Meanwhile, Najib also noted that international reserves had fallen US$8.3 billion since mid-April.

During his administration, international reserves sank to a six-year low in August 2015, going as low as US$94.5 billion.

However, at that time, the reserves to short-term debt level had remained above 1.0.

The reserves to short-term debt level slid to 0.9 at the end of August this year.

Short-term debts are debts that are due within one year. It is not clear how many of these debts are due for repayment soon.