The Chair of the City Council's Transport Committee says heads need to be knocked together to fix an issue affecting Dublin Bikes customers.
Subscribers who use Ulster Bank debit cards haven't been able to rent a bike since the middle of July, because of an IT issue.
The 78 people affected are being advised to use an alternative debit or credit card if possible, until the problem is fixed.
33 of those affected have since switched to using a different method of payment, but another 45 still haven't been able to rent a bike because of the issue.
Only Ulster Bank debit cards are affected, while the bank's credit cards and debit and credit cards from all other lenders are working fine with the service.
There is no known timeline for a fix.
Green Party Councillor Ciaran Cuffe says neither side appears to be offering a solution.
"Dublin Bikes don't seem to be able to fix it and neither does Ulster Bank, so I think we really need to knock heads together and tackle this", he said.
The The Chair of the City Council's Transport Committee also said it seemed "absolutely wrong in 2018 that a banking system can't work with a simple service that is there to help the city".
An Ulster Bank spokesperson said they are "aware of an issue whereby transactions from Dublin Bike terminals using Ulster Bank debit cards are no longer coming through to Ulster Bank in a recognisable format."
"We are working with the retailer to support them in resolving the issue as soon as possible. We apologise for the inconvenience.”