Singapore's growth in the third quarter badly missed expectations on Friday, potentially signaling weakness around the region.

The city-state's gross domestic product (GDP) grew 0.6 percent on-year in the third quarter, well off forecasts for 1.7 percent growth from a Reuters poll and the weakest reading since 2009, during the global financial crisis.

GDP also contracted 4.1 percent on-quarter, compared with a Reuters poll forecast for 0.3 percent growth.

"Singapore being a small open economy, basically we are like a harbinger," Selena Ling, head of treasury research and strategy at OCBC, told CNBC's "Squawk Box" on Friday. "You can expect the next few weeks when we get third quarter growth numbers coming out from the rest of the Asian economies, probably you'll see weaker than expected numbers as well."

She called Singapore's data "pretty grim," noting that even the most bearish forecast hadn't called such weak figures.

Despite the weak data, Singapore's central bank, the Monetary Authority of Singapore (MAS) kept its monetary policy unchanged with a neutral bias for the currency.

Rather than using interest rates, the MAS, which has official policy-setting meetings just twice a year, sets its monetary policy by adjusting an undisclosed trading band for the currency based on a basket of currencies weighted to reflect trade levels with the city-state.