A weak magazine market hit the retailer's bottom line
The expansion plan is a response to an 8% fall in pre-tax profits to £130m for the 12 months up to August this year, a period when its news distribution business was hit hard by a weak magazine market.
But the company insists that its future is bright, despite worries about the strength of the UK economy.
"WH Smith has in the past proved to be quite resilient to recession because the things that we sell, such as magazines, newspapers, stationary and so on are daily necessities," managing director of UK retail, Beverley Hodson told BBC News 24.
Northern Ireland
The boost to its business over the next three years will involve a move beyond its traditional High Street, airport and train station locations and the opening of shops in Northern Ireland.
"We did a considerable amount of customer research there and identified that there was a gap in the market for WH Smith," Ms Hodson said.
Its first shop in Northern Ireland was opened last week.
"It took us some time to locate the best site for our first store," Ms Hodson said.
"We opened just recently in Belfast and we plan to assess the performance of the Belfast store before we embark on a major opening push in the region," she said.
"The move into the [Northern] Irish market forms part of the future growth strategy, which aims to stretch the brand into new markets both in the UK and abroad," the retailer said.
New formats
The company will also test out new ways of organising its outlets by offering coffee shop facilities, audio and video systems, and by selling non-traditional products.
And it will open up shops on the edges of towns, as well as factory outlets.
Last year, the company opened 29 new shops.