Representatives from the Communication Workers Union (CWU) and mail chiefs will meet in London to try and find a solution to the dispute over jobs, pay and modernisation.
The third wave of 24 hour national stoppages is planned for this Friday (6 November) and the following Monday (9 November) and is set to involve all 121,000 members of the postal workers union.
The planned stoppages follow the three-day walk-out last week and an earlier two-day strike last month.
Royal Mail says that 25% of its delivery staff worked on Saturday, the third day of the latest round of action, a figure disputed by the CWU, which says there is solid support from its members.
The two also disagree on the backlog caused by the strike, with the Royal Mail putting the figure at 35 million items, while the CWU says the total of undelivered mail has increased to over 100 million.