Associated British Foods said that unusually warm winter weather meant sales at its Primark discount fashion chain stalled in the nine weeks to January 2.
The drop was shrugged off by the fast-growing retailer as a temporary blip.
Consumers avoided buying winter clothes during some of the mildest November and December temperatures on record, with retailers Next and Marks and Spencer blaming the weather for disappointing sales before Christmas.
Primark, which trades as Penney's here, sold fewer coats, hats, scarves and thermal clothes. This caused sales at shops open more than a year to fall in the nine weeks to Jan. 2 compared with the same period the year before.
AB Foods also has major sugar, grocery, agriculture and ingredients divisions. Since hitting an all-time high in early December, shares in the company have lost 16% on concerns about the impact of the weather.
But the picture for the 16-week period to January 2 was mixed, with Primark saying it posted "strong" like-for-like sales growth in the first seven weeks.
AB Foods finance director John Bason said the weaker pre-Christmas performance was nothing to worry about.
"Footfall was fine. It's specific to those weather related items," he told Reuters. "We'll move on from that."
On a total sales and constant currency basis, Primark's sales climbed 7% over the 16 week period, in line with the increase in selling space from new shops, including in the US and Spain.
Primark plans to open six more stores in the US this year and will also open its first outlet in Italy in the summer, building on its portfolio of 299 shops.
For its 2015/16 financial year, AB Foods stuck with its current forecast for a modest decline in adjusted operating profit, brought about by currency pressures.
The group today also reiterated expectations for an improvement in sugar profits in 2017.
