Monday's meeting will decide whether the overwhelming vote by Communication Workers Union members in favour of a strike will translate into action.
The union, which must give seven days' notice of a strike, revealed yesterday that 76% of members balloted last month were in favour of industrial action.
Dave Ward, deputy general secretary of the CWU, said it would give Royal Mail a "final opportunity" to resolve the row over working practices, pay and job cuts over the next ten days.
Underlining the bitterness of the ongoing dispute, which has already brought several local strikes, Royal Mail condemned further strike action as "deplorable and irresponsible" and said 60% of its workers did not vote to strike.
Online and catalogue retailers are now scrambling to make contingency plans to avoid disruption to deliveries, while consumers are expected to bring forward online Christmas shopping or rely more on bricks and mortar retailers.
A survey of 250 businesses released yesterday by the British Chambers of Commerce found that three-quarters were considering using another delivery service.
if a national strike goes ahead, while eBay has decided to suspend the ability to rate sellers on their dispatch time.
The Direct Marketing Association has attacked the government over the disruption. DMA head of membership and brand Robert Keitch said it was a "disgrace", that the government as Royal Mail's shareholder, was not intervening. to put its point of view.
Robert Hammond from watchdog Consumer Focus urged companies which fulfil orders via delivery to make their plans clear to consumers via their websites.