The CWU's postal executive is currently working on its proposal, but at the same time is preparing its next phase of strike action. It said it would communicate details of the action before the end of this week.
Last week, it broke off talks with Royal Mail and rejected its offer, threatening further strikes before the end of the month. It said it could not accept Royal Mail's proposals on pay, working flexibility and pensions.
According to the union, the pay options outlined by Royal Mail amounted to a 6.7% increase on basic pay over two years with additional lump sums.
Since then the two sides have had another meeting at which Royal Mail invited the union to table a counter proposal with a view to resolving the dispute.
The union will write to members to give details of its counter proposal and to emphasise to need for them to continue to support strike action.