The Irish Medical Organisation (IMO) is to begin balloting its consultant and non-consultant hospital doctor (NCHDs) members on possible industrial action.
The move is over what the union said was a crisis in medical manpower and lower salaries for more recently appointed consultants.
The result of the ballot will be known on 17 December.
The union is seeking a mandate for action, up to and including withdrawal of services.
Last week, Minister for Health Simon Harris said he would table an offer to doctors within weeks.
