New figures show complaints and enquiries to the office of the banking ombudsman have risen rapidly but the number of disputes requiring investigation is down.
In the financial year to 20 June 2011, it completed 1,857 and helped over 4,000 people resolve disputes with their bank.
Banking Ombudsman Deborah Battell says that's down 18% on the previous year.
Investment-related issues, including the collapse of I-N-G New Zealand funds, dominated workloads then.
Ms Battell says a lot of the complaints and enquiries are about the way banks handle individual cases.
These included how they dealt with loan defaults and incidents where promises were made to customers to lend them money but the loan was never forthcoming.