Primark has warned it expects to post a fall in like-for-like sales during its first half after performance was hampered by “unseasonably warm weather in October”.

The fashion giant’s owner Associated British Foods said in a pre-close update that same-store sales are expected to suffer a 1% decline during the 24 weeks to March 3. 

It blamed the warmer weather for a “significant decline” in sales during October.  

Despite the anticipated like-for-like decline, Primark said total sales across the group are expected to be 7% up compared to the same period last year on a constant currency basis – and 9% higher at actual rates. 

Sales in its UK arm grew 8% year on year, while like-for-likes advanced 4%.

This was largely driven by its store opening programme and expanded ranges.

Primark also hailed an increase in its market share, amid a volatile sector.

The value fashion operator reported “record” sales in the week before Christmas, although it did not disclose a specific figure.

Primark said it plans to press ahead with its aggressive store opening programme, with a goal of adding 1.2 million sq ft of selling space in the current financial year.

New stores are poised to open at Westfield London, Toulouse and Metz in France, Munich in Germany, Antwerp in Belgium, Valencia in Spain and Brooklyn in the US.

ABF said it expects an “acceleration” in profit growth at Primark during the second half as a result of an improvement in margins.

The business said “better buying” and some benefit from the recent weakness in the US dollar would aid margin gains.