ATHENS (Reuters) - Greece on Monday said it would conduct its bond buyback offer through a modified Dutch auction method in which investors declare how much they are willing to sell their bonds at before the price is determined.

Greece set a minimum price range of 30.2 to 38.1 percent and a maximum price range of 32.2 to 40.1 percent depending on the bond maturities on the 20 series of outstanding bonds.

Athens said it would not spend more than 10 billion euros on the buyback. Investors must declare their interest by December 7 and the expected settlement date is December 17. The bond buyback is crucial to Greece's efforts to unlock aid to keep afloat.

(Reporting by George Georgiopoulos, Writing by Deepa Babington)