By Davide Barbuscia

DUBAI, Jan 4 (Reuters) - Dubai Islamic Bank DISB.DU (DIB) has asked banks to submit proposals to arrange a potential U.S. dollar-denominated sukuk issue, sources familiar with the situation said on Wednesday.

The planned debt transaction would be of benchmark size, which usually means upwards of $500 million, said the sources, adding that the request for proposals was sent a few days ago. A DIB spokesman was not immediately available to comment.

The Islamic lender joins a number of banks in the Gulf region planning to raise debt internationally to improve their liquidity, which has been squeezed by low oil prices.

Among them, Bahrain's Gulf International Bank GLFBK.UL and Kuwait's Warba Bank WARB.KW have in the last few weeks appointed banks for conventional and Islamic bond issues respectively.

DIB's latest sukuk sale was a $500 million, five-year issue in March last year which offered a 3.6 percent profit rate. The bond, listed on the Dubai Financial Market and on the Irish Stock Exchange, was part of a $2.5 billion sukuk programme.

It also has an outstanding $300 million sukuk maturing imminently, issued in 2012 by DIB's subsidiary Tamweel, a Dubai-based sharia-compliant mortgage provider. That bond has a 5.15 percent profit rate.

Dubai Islamic Bank is rated Baa1 by Moody's and A by Fitch.

(Editing by Andrew Torchia) ((Davide.Barbuscia@thomsonreuters.com;))