Westpac's full year net profit has fallen by 15 per cent to $5.97 billion due to the tax implications of its takeover of smaller rival St George.
The result for the year to September 30 was down from $6.99 billion in 2010/11, when Westpac received $1.1 billion in tax benefits.
The 2011/2012 result includes $165 million in retrospective tax charges.
Westpac's cash earnings in the 12 months to September 30, which takes out one-off financial items, rose five per cent to $6.598 billion compared to the previous year.
The cash result was above analysts' expectations of $6.46 billion.