* Indonesian rupiah, Australian dollar hurt 2013 earnings
* Says forex to hurt first-half results especially
* Says to focus on margin improvement, price increases
* Full results due March 19 (Adds 2013 targets, comment on margins)
FRANKFURT, Feb 6 Germany's HeidelbergCement warned that exchange rate fluctuations would continue to impact its earnings this year after a weaker Indonesian rupiah and Australian dollar caused it to fall short of its own targets for 2013.
"The decline in exchange rates in the second half of 2013 will also impair our revenue and results, particularly in the first half of 2014," Chief Executive Bernd Scheifele said in a statement.
HeidelbergCement had initially aimed to increase revenue and operating profit for 2013. But it warned in November that it was becoming harder to achieve those goals as rising sales volumes, price increases and lower energy and raw material costs could not fully offset negative currency effects.
Preliminary financial results published on Thursday showed that revenue eased by 0.6 percent to 13.94 billion euros ($18 billion), compared with consensus for 13.99 billion, while operating profit was virtually flat at 1.61 billion.
HeidelbergCement, the world's fifth-biggest cement makers, said it would continue to focus on improving margins, raising prices and regaining an investment grade credit rating.
HeidelbergCement is due to publish full 2013 results on March 19. France's Lafarge and Holcim, the world's two largest cement makers by production capacity, are due to publish results on Feb. 19 and Feb. 26, respectively.
($1 = 0.7390 euros) (Reporting by Maria Sheahan; Editing by Victoria Bryan)