After a PS1 charge on all hospital cash machine transactions on Monday, the Belfast Trust has apologized to staff and patients.
The trust claimed it had no control over the decision because the machines were provided by a private company.
Unison, a trade union, has asked its members to boycott the machines.
Conor McCarthy from the union called for the private company's reconsideration, saying that "we are facing a cost-of-living crisis".
He said, "I want them take into consideration the current environment in which they are implementing these fees."
These are also NHS hospitals. The staff who worked during the pandemic should be granted free access.
Paula Bradshaw, Alliance's spokesperson for health, urged trust members to keep in touch with the cash machine supplier.
She stated that it was an urgent matter because people may need access to machines in an emergency or time of distress.
Belfast Trust reported that it has introduced contactless and card payment systems to its canteens, vending machines and shops.
According to the trust, it will not gain any financial benefits from the introduction of the charge.