There are concerns phasing out cheques may make it harder for the elderly to get around.
Kiwibank has announced it will get rid the payment method by next February, with less than 1 percent of its customers still using them.
"We've chosen not to invest in a shrinking service and outdated technology," said chief executive Steve Jurkovich. "Instead we're moving forward and equipping customers for a world that is increasingly digital."
Age Concern spokesperson Hanny Naus says some elderly may struggle to adapt.
"They may be carrying more cash in the house... they certainly will be at more risk of being abused because they are more isolated, they can't get out and about."
The bank says support will be available to teach those affected how to use online banking.
"We understand cheques may still play a role in the day-to-day lives of some of our customers," said Jurkovich.
"For this reason, we wanted to provide customers with plenty of time to prepare for this change."
Naus says it might not be enough time for some to learn.
"There is an assumption that once you know it once, you'll be able to carry on that way. Then any other option gets taken away. That's happening not just in the banking sector, but in Government and many other sectors," she told Newshub.
"We need to have that support ongoing so there's always going to be an option for people to have face-to-face support or direct phone support, so they're not talking to machines."
The bank says online banking is much safer and easier to process.