By Marc Jones and Sarah Morris

LONDON/MADRID (Reuters) - Airport operator BAA plans to announce refinancing of a significant chunk of its 10 billion pound ($20 billion) debt in the next week along with a 700 million pound property sale, a source close to the deals said on Monday.

BAA, owned by Spain's Ferrovial (FER.MC: Quote, Profile, Research), is expected to launch syndication of a 1.2 billion pound loan.

The loan is being arranged by Australian bank Macquarie (MQG.AX: Quote, Profile, Research), The Times said in a report on Saturday.

The source added that BAA will announce the 700 million pound sale of its industrial property portfolio to U.S. firm ProLogis PLD.N.

The portfolio comprises over 50 commercial buildings on the periphery of its airports, which include Heathrow, Gatwick, Stansted and Glasgow.

Both Ferrovial and BAA declined to comment.

Last month, Ferrovial agreed to sell about a quarter of its Airport Property Partnership (APP) joint venture to Arora Family Trust for 265 million pounds.

Part of the proceeds from the sale would be used to repay APP's existing debt, and the balance after costs would be returned to BAA and its joint venture partner Morley Fund Management, which owns 50 percent of the venture.