The expansion comes just days after the retailer secured new loan funding to maintain its investment plans.
Poundland also confirmed it would open the first of over 30 Republic of Ireland Pep&Co concessions in its Dealz stores before Easter.
Adrian Mountford, Pep&Co managing director, said: “This Christmas we sold over a million more items than we did in our whole first year of trading from standalone stores.
“Thanks to our partnership with Poundland – and now Dealz in the Republic of Ireland – we’re set to double in size over the coming year, helping us to drive economies of scale to keep prices low, helping make Poundland an increasingly popular new fashion destination.”
Barry Williams, Poundland managing director, added: “Who would have thought 12 months ago that we would make Poundland a must-stop fashion destination.
“Well we’re turning that ambition into reality and by the end of this year, with over 300 ‘shop-in-shop’ fashion stores, we’re set to become a major fashion player.”