SYDNEY, Dec 31 - Loss-making Australian property trust GPT Group (GPT.AX) has agreed to sell the rest of its U.S. shopping mall portfolio for nominal amounts, with the buyers to take on the malls' associated debts, GPT said on Thursday.

The malls were held through GPT's joint venture with ailing Australian infrastructure group Babcock & Brown. GPT did not name the buyers.

(Reporting by Mark Bendeich; Editing by Tim Wimborne)