The Banking Ombudsman is expecting more complaints from ANZ customers who were advised to put money into ING's frozen investment funds.
ING's Diversified Yield Fund and Regular Income Fund were frozen last year as their values collapsed amid the global credit crunch.
The company, which is 49% owned by ANZ, made a revised final offer which included the proviso that investors who agreed to the deal would not start, or continue, any legal action related to the funds.
Banking Ombudsman Liz Brown says she understands why the offer has been framed in this way, as the bank is concerned that some people might make complaints that are not meritorious, but she is also concerned about the effect on elderly, unwell customers.
Ms Brown says her office has already received up to 400 complaints from the 2,700 ING investors who were advised by ANZ, and will accept more.
Of the 100 cases which have been completed, Ms Brown says some were an agreed settlement, some were found in favour of the complainant and others in favour of the bank.