Currencies in Indonesia and Malaysia have already taken a beating over the past year, and the interest rate increases in the U.S. are set to deal them another blow.
"These two are a little bit more vulnerable to Fed hikes, tightening in dollar liquidity (and) capital outflows," Mitul Kotecha, head of Asia foreign-exchange at Barclays, told CNBC Thursday. "Both currencies may be more susceptible to weakness as we go into next year."
That's in part because both countries are commodity exporters. Higher U.S. interest rates are set to boost the U.S. dollar, which will weigh on the prices of dollar-denominated commodities.
Sharp drops in the prices of the two country's commodity exports, have helped to weaken their currencies to levels last seen during the 1998 Asian Financial Crisis. The U.S. dollar has strengthened around 24 percent against Malaysia's ringgit and nearly 14 percent against Indonesia's rupiah so far this year.
On Wednesday, the U.S. Federal Reserve raised its target federal funds rate to a range of 0.25 to 0.5 percent on Wednesday, marking its first rate increase since June 29, 2006.
Partly due to the rate hike, oil traded lower in the U.S., with crude oil futures settling Wednesday at $35.52 a barrel, down $1.83, or 4.90 percent, after weekly EIA crude inventories showed a rise of 4.8 million barrels.
Pressure on energy prices will be compounded by a mild winter in the U.S. and that will hit both Malaysia and Indonesia, Robert Rennie, global head of foreign-exchange strategy Westpac Bank, told CNBC Thursday.
"If I'm right (and) the momentum in U.S. data picks up in the first quarter, that's something that accentuates (that), so I think the idea is that really we continue to see capital flight out of Asia (and) underperformance in Malaysia and Indonesia, hit by the commodity story as well," Rennie said.
Barclays has also pointed to concerns over the effect of lower oil prices on the rupiah and the ringgit.
"A potential further decline in oil prices from current levels remains the biggest 'known unknown' and has the potential to weigh on emerging market assets globally, especially on the commodity exporters (and not coincidentally high betas) of Malaysia and Indonesia," Barclays said in a note Thursday.
Still, Kotecha noted that the currencies' declines in the year ahead aren't likely to be as bad as in the year just completed.
"The ringgit is already very cheap. It's already weakened a lot," he noted. "The pace of weakness might be more moderate. And even Indonesia, there is some potential upside here. The yield is pretty high and that makes it quite difficult for investors to go short this currency. We're not looking for either to fall out of bed."
Bank Indonesia is expected to keep its interest rate at 7.5 percent at its meeting Thursday, but some analysts are forecasting a cut in January.
—By CNBC.Com's Leslie Shaffer; Follow her on Twitter