The vice-chairman of Fine Gael in the Cork South-West constituency has been forced to resign after posting social media comments about the brother of a government minister in the county who has pleaded guilty to selling black-market cigarettes.

Peter Walsh, a former Clonakilty town councillor, resigned last week after his constituency chairman told him he had consulted Jim Daly, a local TD and a junior minister for health, on the issue.

Walsh, who runs a newsagent’s in Dunmanway, said he has long campaigned to highlight how the sale of black-market cigarettes damages “legitimate traders”. The shopkeeper, who was Fine Gael’s social media officer for the constituency, used his personal accounts to highlight the case of John Daly, a postmaster in Drinagh, who has pleaded guilty