JD Wetherspoon, which has five pubs in Northern Ireland, has blamed the timing of the early May bank holiday for hitting third-quarter sales, while bemoaning "significant cost increases" in the second half of the financial year.
The pubs company logged a 3.5% increase in like-for-like sales for the 13 weeks to April 29, while total sales increased 2.8%.
It said the rate of growth was slowed by the May Day break, which was included in the third quarter in 2017, but failed to make the cut-off this year - making for tougher comparatives.
In its trading update, JD Wetherspoon said it is "likely to have reduced like-for-like sales by about 0.5% in the period".
Chairman Tim Martin flagged higher costs and further uncertainty around the forthcoming World Cup in Russia.
"As anticipated, the rate of like-for-like sales growth slowed slightly in the third quarter.
"We continue to face significant cost increases in the second half in areas which include labour, business rates and the sugar tax. There is also some uncertainty as to the effect on sales of the Fifa World Cup. We continue to anticipate a trading outcome for this financial year in line with our previous expectations."
JD Wetherspoon shares were down 0.3% in morning trading. It also detailed the opening of five new pubs since the start of the financial year - though 19 were sold off.
Speaking to the Belfast Telegraph last month, Tim Martin said there had been no movement on two proposed Belfast bars because of Northern Ireland's "arduous licensing procedures".
Mr Martin said the sites - at a former JJB Sports store on Royal Avenue, which had previously been refused a licence, and a church building on University Road - were being held back because of taxing licensing application procedures here. He said the delays were "slowing down investment".