Irish households will spend an average of €2,690 in shops this December.
Retail Ireland says this is around €866 more than any other month of this year - and roughly 3% more than Christmas 2017.
Its Christmas Retail Monitor predicts an increase in total sales of over €150m, with sales over the Christmas season expected to top €4.65bn - up from €4.5bn in 2017.
It says the rise in spending will be mainly down to rising disposable incomes, falling prices and a record number of people at work.
But it says with a greater number of Irish shoppers shopping on foreign websites, the challenge will be to ensure this buoyancy "is felt locally".
Meanwhile it says a strong online performance over Black Friday weekend impacted footfall in traditional 'bricks and mortar' outlets.
But local retailers are reporting a significant increase in sales in their own online stores also.