The country's largest lender, ANZ New Zealand, has lifted its profit and says it is gaining customers rather than losing them after merging its brands last month.
The bank made an underlying profit of $1.368 billion in the year to September, an increase of 10% compared with the previous year.
Following the merger of the ANZ and National Banks, competitors launched advertising to try to attract customers away from the bank.
ANZ chief executive David Hisco says the bank has been working to simplify its business and hold on to customers.
He says it has done quite a bit of business out of the rebrand and mortgage sales since then have also increased.
"There's been no appreciable uplift and in fact our net numbers are better than they were."
The ANZ and National Bank systems will be merged this weekend into one technology platform.
Mr Hisco says rigorous testing has been carried out, including four full rehearsals of the conversion, and the project is ready to go.
In profit figures announced on Thursday, the bank said net interest income rose 4% to $2.7 billion due to people switching from fixed to floating mortgage rates, which is more profitable for banks.
Lending increased 3% to $88 billion driven by loans to small businesses, while deposits grew strongly - up 9% to $50 billion - despite keen competition.
The amount set aside to cover potentially bad loans rose by 4% to $195 million, but the bank says it managed to keep a lid on costs.
Overall, ANZ's profit rose by 6% to $A6 billion, driven by an improved second half for the Australian division and growth in its institutional banking, particularly in Asia.