Indonesia could achieve another rating upgrade if it can tackle problems with infrastructure, crack down on rampant corruption and prepare measures to mitigate external shocks, says Fitch Ratings, which last month raised the nation's sovereign rating to investment level.

Fitch raised Indonesia's long-term sovereign debt rating to BBB-, the lowest investment grade, from BB+ on 15 Dec., citing the country's robust economic growth, prudent fiscal and monetary policies. The outlook is positive, which means that Indonesia is inclined for a rating upgrade.

A further upgrade is not likely to take place in the next 12 to 24 months, but added that there were ways to accelerate a rating upgrade, according to Philip McNicholas, Fitch Ratings's director for Asia-Pacific sovereigns.