State-owned Kiwibank today announced a profit of $5.4 million after tax for the six months ended December 31.
This compares with a profit of $2.5m for the corresponding period in 2004.
Chief Executive Sam Knowles said the bank was on track to exceed last year's full year profit of $7m.
"Clearly this year is going to be bigger and better. We are exceeding expectations in all areas and have passed the milestone $2 billion mark for home loans."
He said the bank, fully owned by New Zealand Post, had continued its rapid growth in all key target areas. It now had over 400,000 customers.
Home loans increased 35 per cent from $1.50 billion to $2.03 billion. Retail deposits increased 23 per cent from $1.30 billion to $1.60 billion.
Mr Knowles said it was important that the bank maintained its growth momentum in an extremely competitive environment.
The bank had targeted a customer base of at least 200,000 when established four years ago.
It was continuing to sign up an average of 450 new customers every business day.
"The figures prove conclusively that there is a place for a New Zealand-owned bank with better service, better interest rates and lower fees than the foreign-owned banks."
Mr Knowles said steady growth of business banking was very pleasing.
Kiwibank had 12 business banking centres operating in seven cities and would continue to extend this network to other parts of the country.
The bank incurred a $2.7m tax charge for the six-month period.