The Communication Workers Union has announced two more strike days for 6 and 9 November.
Unlike the current industrial action, the two new dates will be all-out stoppages.
Meanwhile, the backlog of undelivered mail caused by the strikes has risen to 35 million items, Royal Mail has said.
John Moylan reports.
One-Minute World News 
Bookmark with:
What are these?
E-mail this to a friend