Casual apparel giant Gap Inc on Thursday showed more signs of its recovery as it posted a 10 per cent jump in May same-store sales on the back of strong women's sales and more focused marketing.

The California-based operator of more than 4,200 stores said in a statement total sales at its banners in the four weeks to May 31 climbed 14 per cent to $1.1bn from $995 million in the year-ago period.

The company said same-store sales at its Gap US division rose eight per cent with Gap International comparable sales up 17 per cent.

It added same-store sales rose two per cent at Banana Republic last month and 13 per cent at Old Navy.

"We're pleased with our double-digit positive comparable store sales performance for May," said Sabrina Simmons, senior vice president, treasury and investor relations.

"All divisions reported positive comparable store sales, and total company sales and merchandise margins met beginning of month expectations. Markdown margins improved and we ended May with a lower percentage of inventory at markdown than last year.

"While Gap's men's business was weaker than expected, women's summer product performed well, with our advertised women's tunics continuing to be a summer fashion standout," she continued.

"Old Navy continued its momentum, with strong summer product assortments and effective promotional pricing strategies driving performance."

Gap also revealed year-to-date net sales of $4.5bn for the 17 weeks ended May 31, up 15 per cent on last year's sales of $3.9bn. Year-to-date same-store sales rose 12 per cent versus a year-ago fall of 16 per cent.