ASB Bank said a resilient New Zealand economy and low levels of bad debt helped the bank to achieve a record statutory net profit of $372 million for the first half to December 31.
The result was a 31.4 per cent improvement on the same period a year earlier, but the bank warned that the outlook for the second half would be clouded by Europe's economic woes.
A positive $48 million adjustment in the fair value of its derivatives, which the bank is obliged to do under "marked to market" accounting rules, was a factor behind the big increase in the headline profit number.
Excluding these movements from both periods, the statutory net profit would have grown by 12.9 per cent.
Asked if she expected to see a backlash over the bank's high earnings, ASB chief executive Barbara Chapman said: "The profit as a headline number does look large, but you do need to put that into a New Zealand context and we are very large businesses.