Specialty clothing retailer Gap Inc has reported 3% growth in February comparable store sales, driven by an extra week during the month and gains from its acquisition of multi-brand women's wear retailer Intermix.

Net sales increased 11% to US$966m during the four weeks ended 2 March, compared with $874m the same period last year.

The San Francisco-based company said comparable store sales were up 2% at Gap and 6% at Old Navy. However, Banana Republic saw comparable store sales decline 5% during the month, compared with an 11% increase a year earlier.

"Building on our successful 2012 performance, we're pleased with the company's overall sales results in February," said chairman and CEO Glenn Murphy.