Gardden Road practice in Rhosllanerchrugog, Wrexham closed its Hightown branch in October after three of the five partners were unable to work due to illness, a resignation and holidays.
But in a letter to the senior partner Dr Edgar Coward the local health board has threatened to fine the practice £5,000 a month - worth £60,000 per year - for breach of contract until it re-opens the surgery.
Dr Coward told GP he would not be ‘bullied' into re-opening the practice as he believed it would be unsafe to do so due to workload pressures.
‘It is dangerous,’ he said. ‘I am not going to be forced to do something dangerous. If the pilot says a plane is unsafe to fly, should he fly it?
'Workload, excluding increasing list size, is going up by 5% a year. If the numbers are going up as well, then we are really starting to feel the strain. It is getting dangerous. We can't cope.'
Dr Coward said the practice has lost 200 patients since they closed the branch but none have complained and most moved to the practice's other two sites.
He added that recruiting GPs in north Wales was 'extremely difficult'.
A spokesman from the Betsi Cadwaladr University Health Board said: ‘The board has been in ongoing discussion with the Gardden Road practice following its closure of the Hightown branch in October last year due to lack of GP availability as a result of sickness and other issues.
‘We agreed a temporary closure for four weeks to allow the practice to implement actions to rectify the situation and met with the partners and agreed a plan for reopening the branch – this agreed plan was not fulfilled by the practice.
'We are now in a position where the health board has significant concerns regarding the ongoing failure of the practice to provide services in Hightown for the patients that normally attend this branch, some of whom have difficulty in travelling to the main surgery.
‘It is not appropriate for us to disclose details of contractual discussions or sanctions which may be imposed on individual practices. However, we can confirm that where a practice has failed to meet the requirements of a remedial notice under the GMS contract then the health board is able to impose contract sanction under the terms of that contract.’