Some 2,000 Post Office workers are set to receive their strike ballot papers on Saturday of this week after pay talks broke down with bosses.
The CWU union is recommending a Yes vote and if members back action strikes could start in December.
Workers in Post Office Admin and Supply Chain grades are furious that bosses have refused to meet their claim for a wage increase.
This is well beyond the 1 April settlement date.
The ballot is due to end on 18 November.