The group said that the growth had been delivered across all key customer groups and product ranges, including a strong performance from women's clothing.
Online sales accelerated to 48% in the period from 40% in the first half and around 28% of group sales now come via the internet.
Gross margin is 0.5% for the 20 week period was down 0.5% against the previous year but N Brown said this was in line with expectations and was due to a change in product mix and customer mix. It said the margin decline had been offset by operational cost savings.
The company said in a statement: "Sales from our established customers have been ahead of our expectations due to higher response rates and an increased average spend, driven by improvements to our product ranges, catalogues and websites."
N Brown said that sales from new customers in the second half of the year had increased by 30%, partly due to increased advertising and the new titles launched in 2007, including Simply Yours, Marisota and Jacamo.