More Kiwis are joining Kiwibank and most of them are banking online, meaning more branches will be shutting in the future.

The bank's reporting a strong after-tax profit of $127 million - $27 million more than last year.

One in four New Zealanders with a bank account now have an account with Kiwibank, and chief executive Paul Brock says that represents a one percent increase in the market share, year-on-year.

He said these customers are increasingly tech savvy, with almost 90% of last year's service transactions happening online and that as digital plays out, it will mean fewer branches overall.

"We'll continue to change with our customers and we have done that throughout the year, anytime we put out a new digital offering we're getting very strong uptake from customers."

The bank's space-sharing relationship with Post Shop is set to change and customers may have the option to bank in book shops and other local businesses, in the future.