National Australia Bank Q1 cash profit up 6 pct

SYDNEY, Feb 5 (Reuters) - National Australia Bank on Thursday posted a 6 percent gain in first quarter cash profit after booking a small gain on sale of part of its UK commercial property loans and higher revenue at home.

NAB, the fourth biggest bank by market value, posted cash profit of A$1.65 billion ($1.28 billion) for the quarter-ended December. Revenues rose 4 percent including the sale of the UK property loan portfolio.

Net interest margin, a key gauge of profitability for lenders, was flat and indeed slightly lower excluding the company's markets and treasury divisions. Charges for bad and doubtful debts jumped 30 percent to A$227 million but NAB said that was stable when economic cycle adjustments and provisions for the UK property portfolio were removed.

NAB sold 1.2 billion pounds ($1.8 billion) of mostly non-performing UK commercial property loans in December, reducing the portfolio to 836 million pounds compared to 5.6 billion in October 2012.

NAB's statutory net profit of A$1.8 billion versus the A$1.4 billion it reported a year ago. However the bank did not give a year-ago comparison in its trading update, which does not provide as much detail as a full earnings statement. ($1 = 1.2873 Australian dollars) ($1 = 0.6586 pounds) (Reporting by Swati Pandey and Lincoln Feast; editing by Andrew Hay)