Complaints about bank lending-related matters rose sharply in the last three months of 2021, according to the Banking Ombudsman.
Latest data indicates complaints about home loans rose 24 percent and about credit cards by 19 percent between October and December, compared with the previous three months.
Complaints about long waiting times for a loan decision rose 62 percent on the previous quarter, while complaints about declined applications were up 22 percent.
Banking ombudsman Nicola Sladden said she was not surprised by the increase because it coincided with the introduction of amendments to the Credit Contracts and Consumer Finance Act.
The legislation required lenders to scrutinise customers' expenses more closely when assessing loan applications, along with other measures designed to protect vulnerable consumers.
"We knew some customers wouldn't be happy about this greater level of scrutiny - or the resulting longer processing times," Sladden said.
"We issued a guide in October to help customers prepare for the changes, but many would still have been caught by surprise."
In total, banks received 24,206 complaints during the quarter, up 3 percent on the previous quarter.
Of these, 12 percent were about what customers considered to be a bank's failure to follow through on an agreed action, particularly in lending-related matters.
Sladden said the tightening of loan-to-value ratios and an increase in interest rates during the quarter contributed to the spike in lending-related complaints.
In November, the Reserve Bank halved the amount of low-equity lending banks were able to provide, leading some banks to withdraw or modify pre-approvals issued to borrowers with deposits of less than 20 percent.
The scheme also received more lending-related complaints between October and December, with a doubling of concerns about delays and banks not acting as promised, as well as a significant increase in concerns about unfair fees and rates.
On a more positive note, she said there had been a drop in the number of complaints related to financial hardship, which indicated the banks were managing those more effectively.