More than 2,200 complaints have been made against financial institutions so far this year.
The Financial Services Ombudsman Joe Meade said grievances in the first five months of the year were up 29 per cent on the same time last year.
Mr Meade said the era when insurance and investment companies could take advantage of anyone, especially the elderly and disadvantaged by selling inappropriate products, is over.
He told an Experian business lunch in Dublin that institutions had to ensure customers were made fully aware of all the features sand potential downsides of products before the sales are complete.
"It is vital that financial services companies ensure that staff are fully trained in the products they sell and that the organisations management take responsibility for their sales staff to ensure that customers receive the
highest level of advice on product sales," said Mr Meade.
"Paper procedures are no use if they are not carried out in reality. Staff must not only be well trained but management must ensure that sales practices are carried out to the highest levels."
Since it opened three years ago, the Office of the Financial Services Ombudsman has received over 14,000 complaints.
Mr Meade said approximately 60 per cent of cases brought to his attention are upheld, but he maintained his office still only receives a small percentage of complaints compared to the number of financial transactions undertaken each year.
"It is a simple truism that if you treat customers fairly than business will thrive," Mr Meade added. "So I say to financial institutions - please improve and ensure that customer care is your number one business goal."
PA