Reuters - Indonesia posted its third straight monthly trade surplus in December and its biggest in two years, in a welcome sign for Southeast Asia's biggest economy amid investor worries about turbulence in other emerging markets.

The trade surplus in December totalled $1.52 billion, the largest since December 2011, the statistics bureau said on Monday. That followed a revised $790 million surplus in November and was more than double the median estimate of a $550 million surplus in a Reuters poll of economists.

Indonesia's rupiah - one of the so-called Fragile Five emerging market currencies - slid more than 20 percent in 2013, hit by investor unease about the country's high current account deficit and the impact of a reduction in U.S. monetary stimulus.

But the rupiah has held largely steady so far in 2014, helped in part as the Indonesian central bank has raised interest rates aggressively since last June. The rupiah pared earlier losses to trade at 12,215 per dollar following Monday's data.

"Definitely, this is positive for sentiment in the markets, and it will be interesting how much of an impact this latest number will have on the current account data for 4Q13," said Gundy Cahyadi, an economist at DBS Bank in Singapore.

"We have forecasted current account deficit at 3.4 percent of GDP in 2013, but now see some chance of it coming in slightly narrower than our expectations."

Bank Indonesia, the central bank, estimates the overall 2013 current account deficit would be below 3 percent of gross domestic product, due to improving demand in the fourth quarter.

Exports in December surged 10.33 percent from a year earlier, versus analysts' expectations for a 1.80 percent rise, while imports fell 0.79 percent, against a forecast 3.60 percent drop.

For 2013, exports fell 3.92 percent and imports dropped 2.64 percent.

Meanwhile, Indonesia's consumer price index rose 8.22 percent in January from a year earlier, the statistics bureau also said on Monday, after torrential rain and natural disasters disrupted activity.

The result was in line with an 8.38 percent increase projected in a Reuters poll of economists, and marked the seventh straight month that annual inflation has stayed above 8 percent.

Core inflation, which excludes administered prices and volatile food prices, quickened to 4.53 percent in January, mainly due to the weakening of the rupiah.

For 2013, inflation surged to 8.38 percent following a surge in fuel prices and disruptions to the food supply stemming from adverse weather.

Some analysts feel Bank Indonesia should increase its key reference rate in the first half of 2014 to contain inflation and possible outflows after the U.S. Federal Reserve's tapering, even at the cost of lower economic growth.

The central bank since June has raised its benchmark rate by a total of 175 basis points to maintain investors confidence, due to nagging worries about the country's ability to finance its economy.