The last bank in Llangollen is to open just three days a week from the end of July with Barclays saying they cannot guarantee it's survival for more than six months.
The branch is the last bank in the whole of Clwyd South.
County councillor Graham Timms contacted Barclays after it emerged the company wants to reduce opening hours in Llangollen to three days a week from July 24.
“We simply cannot lose this bank. I will be writing to Jonathan Brenchley, Barclays’ head of corporate relations in Wales, to try and get some answers,” said Cllr Timms.
Plaid Cymru AM Llyr Gruffydd contacted Barclays seeking assurances, but says he was disappointed with the reply.
Mr Gruffydd said: “We already know that bank lending to businesses falls when banks close, and the fall is significantly more when the last branch closes in a community. Llangollen and the area have been hit by the closures of HSBC and NatWest.
"Barclays argue that cutting opening hours is an attempt to keep a branch open, and I understand that, but the truth is that they cannot guarantee that they will retain a presence there beyond six months.
“While HSBC and NatWest have gone through a significant closure programme, I’m concerned that Barclays will be the next of the big banks to review their presence in our communities across north Wales.
“The Government’s compromise with the British Banking Association which meant that rural communities must have an alternative is flawed and one sided. The BBA will argue that their members provide an online alternative, but the truth is that swathes of North Wales do not have access to Broadband or 3G let alone 4G, and Llangollen and the area is a perfect example."
Labour Assembly Member Ken Skates has also contacted the company.
He said: “Not only is Barclays the only bank in Llangollen, it’s the last remaining branch anywhere in Clwyd South following closures in Brymbo, Cefn Mawr, Chirk, Corwen, Rhos and Ruabon – as well as HSBC and NatWest in Llangollen – in the past few years.”
Last year, Mr Skates received reassurances from Barclays that the Llangollen branch was safe ‘for the immediate future’.
He also encouraged constituents to use the branch as often as they can to keep footfall up.
“In many people’s eyes, reducing opening hours is only a few steps away from closure, so I have asked Barclays for a further commitment to Llangollen,” said Cllr Timms.
“Only once in the past seven years or so has Barclays closed the last remaining bank in any town in Wales, so I hope they will continue to operate with a greater degree of social responsibility than other banks have shown to people in our area.”
Town councillor and former mayor Bob Lube added: “It would be a sad day for Llangollen if this branch closed, particularly after so many people switched when HSBC and NatWest shut.”
The changes will see the branch open on Monday, Tuesday and Friday from 10am-4pm.