According to Canstar's Banking Satisfaction Survey, less than one in four people see their bank as a place to get good financial advice on different products.
The survey findings indicate a potential opportunity for mortgage advisers to grow their customer base, as borrowers remain sceptical about their bank relationships.
The Canstar survey comes as mistrust of the banking sector grows in the wake of the Australian Royal Commission, and subsequent investigations into conduct and culture in the New Zealand financial services sector.
Canstar's survey of 2,500 people compared loan products on customer service, digital banking, problem resolution, fees, products, interest rates, and functionality.
The Co-Operative Bank received the highest customer score. The lender was the only bank to register a top score on customer service, digital banking, and problem resolution. TSB and Kiwibank came in second and third place.
David Cunningham, The Co-Op Bank chief executive, welcomed the survey findings.
"As CEO, if a customer raises an issue with me, I will pick up the phone and call them, and take ownership for resolving the issue. It often surprises customers that the CEO rings them, but it reflects the culture of The Co-operative Bank, with everyone caring deeply about the experience we provide our customers," Cunningham added."
Canstar's survey found New Zealanders have a weak oversight of their finances -- about 60% said they did not stick to a budget each month. The survey also found just 68% of bank customers did not have a savings plan in place.