The brewer said retail beer sales had slipped in the past couple of months, despite a relatively strong performance overall.
The Old Speckled Hen brewer's recent decline is reflected across the UK's off-trade beer sector.
Both ale and lager sales fell 2% in value in the 12 months to April 19 , according to Nielsen figures.
Greene King said its own beers, including IPA and Abbot Ale, had bucked the problems in the take-home market for most of the past year.
Old Speckled Hen grew its volume by 28 % and its share of the premium ale category in supermarkets by 2% to 11.9%.
The brewer said it was committed to "long-term investment" in its own brands, following a £2 million promotional campaign for IPA last year.
Total Greene King revenue rose 5% to £960.5 million, with pre-tax profit up 2% to £142 million.