Robust growth in mortgage loans has spurred a 20 per cent hike in cash earnings for the full year to $5.5 billion for the National Australia Bank Ltd., the nation's best-performing banking stock this year.

For the year to September 30, the National Australia Bank Ltd. registered cash earnings of $5.5 billion, a 19.2 per cent increase a year ago. Total revenue meanwhile came in at $17.6 billion, representing a 5.7 per cent jump on last year's figure, while keeping expenses below inflation rate of 1.4 per cent over the year.

"The National Australia Bank Ltd. has delivered good growth in earnings and revenue and carefully managed costs. In a challenging environment, the balance sheet and capital positions have been strengthened," chief executive Cameron Clyne told the Sydney Morning Herald, noting the latest figures followed efforts to shift the retail banking business over the past two years.

"The increase in earnings was largely driven by revenue momentum in business banking and personal banking in Australia and an improved performance from specialized group assets. New Zealand Banking, United Kingdom Banking and Great Western Bank also contributed," the National Australia Bank Ltd. said in a statement.

Cash profit grew 17 per cent in the second-half as bad-debt charges fell and mortgages grew at more than three times the rate of the industry.

The National Australia Bank Ltd. is Australia's top lender, offering the lowest mortgage rate among the four major banks. Actual second-half cash profit registered at a record $2.79 billion, compared to the $2.8 billion that analysts expected and $2.39 billion reported a year ago.

Earnings from personal banking increased 25.4 per cent to $932 million showing home lending volumes growing three times the market rate.

The National Australia Bank Ltd. reported customer satisfaction levels are at a 15 year high.

"The National Australia Bank Ltd. has outperformed in total lending, achieving strong results across home and business," Sydney-based analysts including Andrew Lyons at Royal Bank of Scotland Group Plc, told Bloomberg.

Shares of National Australia Bank Ltd. have gained 5.3 percent this year, the best performance among the nation's four biggest lenders.