(New throughout, updates with Codelco comment, option price)

SANTIAGO, Jan 2 - Chile's state copper giant Codelco, the world's top copper producer, said on Monday it had exercised its disputed option to buy a 49 percent stake in global miner Anglo American's southern Chilean properties.

Codelco is locked in a legal dispute over the option with Anglo, which surprised Codelco and investors last year by announcing it had sold a 24.5 percent stake in the assets to Japan's Mitsubishi <8058.T>. The move effectively reduced Codelco's potential stake by half.

Codelco viewed Anglo's move as a snub, and says it still has the right to buy a 49 percent stake, saying the price was around $6 billion. Anglo American was not immediately available for comment.

Codelco ... has exercised its right to purchase shares in Anglo American Sur, Codelco told Chile's market regulator in a statement. It said it had exercised its full option to purchase a 49 percent stake.

If necessary, Codelco will exercise all necessary actions to defend and safeguard its legitimate rights and demand the fulfillment of the contract that Anglo American seeks to ignore.

Codelco says Anglo American has reneged on its option contract, and says it has acted in bad faith.

A Chilean court in December maintained a sales freeze on Anglo American's southern Chilean properties, after Codelco filed an appeal to safeguard them, preventing the London-listed miner from selling another part of its coveted assets.

Anglo's properties in southern Chile include the flagship expansion project Los Bronces -- where Anglo has invested around $2.8 billion -- the El Soldado mine, the Chagres smelter and Los Sulfatos and San Enrique Monolito exploration projects.

Anglo American Sur accounted for 41 percent of Anglo's total copper production in 2010. Analysts have estimated the south Chilean assets make up 17 percent of Anglo American's net asset value -- roughly equivalent to its platinum operations.

(Reporting by Moises Avila, Felipe Iturrieta and Simon Gardner; Editing by David Gregorio)